67 killed in Gaza, 7 killed in Israel as UN warns conflict could turn into 'full-scale war'

Jerusalem, Ashkelon and Gaza (CNN) The worst violence in years between Israelis and Palestinians showed no signs of letting up Wednesday, as continued Israeli airstrikes and Hamas rocket fire prompted the United Nations to warn the conflict could mushroom into "full-scale war."

Israel's bombing campaign in Gaza has now killed at least 67 people, including 17 children, and injured more than 388 more, according to the Gaza-based Palestinian health ministry. Israel says at least 15 of the dead were Hamas militants.

"Stop the fire immediately. We're escalating towards a full-scale war," tweeted UN Special Coordinator for the Middle East Peace Process Tor Wennesland. "The cost of war in Gaza is devastating & is being paid by ordinary people. UN is working w/ all sides to restore calm. Stop the violence now."

Militants in Gaza have fired more than 1,000 rockets into Israel since the latest flareup began Monday afternoon, injuring more than 200 Israeli civilians, the Israeli military said Wednesday. A six-year-old boy became the seventh Israeli fatality when a rocket fired from Gaza struck a residential building in Sderot, according to an emergency responder. Around 130 rockets hit Tel Aviv last night, forcing Israel's main international airport, Ben Gurion to close.

Many of the rockets were intercepted by Israel's Iron Dome air defense system, but several struck Tel Aviv, setting a bus ablaze and killing one Israeli woman. Thousands of Israelis spent the night in bomb shelters.

An Israeli soldier was also killed on Wednesday when Palestinian militants fired an anti-tank missile from Gaza, the Israel Defense Forces (IDF) said in a statement. Two soldiers were injured in the same incident, the IDF said.

Photos: In pictures: Violence escalates after clashes in Jerusalem A Palestinian walks next to a building destroyed by Israeli airstrikes in Gaza City on Thursday, May 13. Hide Caption 1 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem Israeli soldiers fire a 155mm self-propelled howitzer towards Gaza from their position near the southern Israeli city of Sderot on May 13. Hide Caption 2 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem Israeli security forces detain a Palestinian man outside the Damascus Gate in Jerusalem's Old City on May 13. Hide Caption 3 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem Julianna Sror views the damage to her apartment after it was hit by a rocket fired from Gaza overnight in Petah Tikva, Israel, on May 13. Hide Caption 4 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem A fireball engulfs the Al-Walid building, which was destroyed in an Israeli airstrike in Gaza City early on May 13. Hide Caption 5 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem A man checks damage following a rocket attack from Gaza in the central Israeli city of Petah Tikva on May 13. Hide Caption 6 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem Muslims perform the morning Eid al-Fitr prayer, marking the end of the holy fasting month of Ramadan in the Aqsa mosque compound in Jerusalem on May 13. Hide Caption 7 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem A passenger rolls his luggage at the nearly deserted Ben Gurion airport in Lod, Israel, on May 13. Global airlines are canceling flights to Israel as clashes intensify between the country's military and Palestinian militants. Hide Caption 8 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem Israeli police patrol Lod during clashes on Wednesday, May 12. Hide Caption 9 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem Mourners surround the body of Lea Yom Tov, an Israeli woman killed by a rocket attack from Gaza, during her funeral in Rishon LeZion, Israel, on May 12. Hide Caption 10 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem Palestinians inspect a vehicle destroyed by an Israeli airstrike after the bodies of its occupants were retrieved in Gaza City on May 12. Hide Caption 11 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem A man walks through debris after a rocket launched from Gaza struck an area in Holon, Israel, on May 12. Hide Caption 12 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem An aerial view on May 12 shows the remains of a Gaza City tower building that was destroyed in Israeli airstrikes. Hide Caption 13 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem Torah scrolls, Jewish holy scriptures, are removed from a synagogue that was burned during confrontations between demonstrators and police in Lod, Israel, on May 12. Hide Caption 14 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem Smoke billows from an Israeli airstrike on the Hanadi compound in Gaza City on Tuesday, May 11. Hide Caption 15 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem An Israeli firefighter extinguishes a burning bus in Holon, Israel, after it was hit by a rocket fired from Gaza on May 11. Hide Caption 16 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem A stun grenade fired by Israeli forces explodes as Palestinians take part in an anti-Israel protest in Hebron, West Bank, on May 11. Hide Caption 17 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem People sit on a staircase of a house in Ashkelon, Israel, as rockets are fired from Gaza on May 11. Hide Caption 18 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem A streak of light is seen from Ashkelon, Israel, as Israel's Iron Dome anti-missile system intercepts rockets launched from Gaza on May 11. Hide Caption 19 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem Palestinians inspect the rubble of the destroyed Hanadi tower after an Israeli airstrike in Gaza City on May 11. Hide Caption 20 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem A damaged house is pictured in a residential neighborhood in Ashkelon, Israel, on May 11, after rockets were fired from Gaza. Hide Caption 21 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem Palestinian children inspect a damaged bedroom following an Israeli airstrike at al-Shati Refugee Camp in Gaza City on May 11. Hide Caption 22 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem Israel's Iron Dome anti-missile system fires to intercept rockets launched from Gaza on May 11. Hide Caption 23 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem Israeli firefighters take cover in Ashkelon as a siren sounds a warning of incoming rockets on May 11. Hide Caption 24 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem Palestinians search for survivors under the rubble of a destroyed rooftop after a residential building was hit by Israeli missile strikes at the Shate refugee camp in Gaza City on May 11. Hide Caption 25 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem Israeli security forces take cover in Ashkelon as rockets are launched from Gaza on May 11. Hide Caption 26 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem The mother of Palestinian Hussain Hamad, 11, is comforted by mourners during his funeral in Beit Hanoun, Gaza, on May 11. The boy was killed during fire between Israel and Gaza. Hide Caption 27 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem Flames and smoke rise from buildings in southern Gaza during Israeli airstrikes on May 11. Hide Caption 28 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem A Palestinian man inspects the rubble of a partially destroyed residential building after it was hit by Israeli missile strikes in Gaza City on May 11. Hide Caption 29 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem An Israeli soldier checks a damaged apartment building in Ashkelon on May 11. Hide Caption 30 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem Israeli rescue teams help residents in a residential neighborhood of Ashkelon on May 11. Hide Caption 31 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem A Palestinian man runs from tear gas during clashes with Israeli security forces at the Aqsa Mosque compound in Jerusalem's Old City on Monday, May 10. Hide Caption 32 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem Israelis take part in the annual Jerusalem Day march on May 10, marking the reunification of Jerusalem after Israel captured the eastern part of the city from Jordan in the 1967 Six-Day War. Hide Caption 33 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem Palestinians clash with Israeli security forces at the Aqsa Mosque compound in Jerusalem's Old City on May 10. Hide Caption 34 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem Palestinians are seen at the Aqsa Mosque compound during confrontations with Israeli police on May 10. Hide Caption 35 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem Israeli police detain a Palestinian during clashes at the Aqsa Mosque on May 10. Hide Caption 36 of 37 Photos: In pictures: Violence escalates after clashes in Jerusalem Palestinians place the Hamas movement flag atop the Aqsa mosque on May 10. Hide Caption 37 of 37

In Gaza, which has few bomb shelters and no air defense system, several buildings and apartments were damaged by Israeli airstrikes. One of those strikes destroyed Al-Shorouk Tower, a 14-storey building in the southern Gaza strip on Wednesday evening, the third high-rise to be targeted in recent days. The IDF said the tower housed Hamas military intelligence offices, as well as infrastructure used by "the terror organizations to communicate tactical-military information."

People in Gaza were in a "state of panic" due to the ongoing Israeli bombardment, said Ashraf al-Qidra, the Palestinian health ministry spokesman in Gaza.

Al-Qidra said Israel had deliberately targeted civilian homes and crowded residential neighborhoods, adding that 43% of the victims of strikes in Gaza were children and women.

Omar Shaban, founder and director of PalThink for Strategic Studies, told CNN that Gazans felt trapped. "I am in Gaza now. I am in my home. I cannot get out. Gaza is too small," he told CNN. "You cannot escape from one place to another place."

People look at a house Wednesday in Yehud, central Israel, after it was hit by a rocket fired from the Gaza Strip.

A destroyed building is seen in Gaza City on Wednesday.

The Israeli military says it does everything it can to minimize civilian casualties when it is carrying out attacks.

Earlier on Wednesday, the Israeli military said it had killed a number of key Hamas officials in a "complex and first-of-its-kind operation" at two separate locations. Among the dead, it said, was a Hamas Brigadier General and the head of the militant group's "cyber and missile improvement system."

Also on Wednesday, Israeli defense minister Benny Gantz said the IDF had hit command squads and Hamas infrastructure in an hours-long "string of serious strikes." "We have hit many hundreds of targets. Buildings are falling, factories are collapsing, terror tunnels are being destroyed and commanders are being eliminated. All means and all options are on the table," he said, speaking in the city of Ashkelon, north of Gaza .

There is currently "no end date" for the military operation against Gaza, Gantz also said.

"When Hamas will stop firing, Israel will stop firing," Israel's Ambassador to the United Kingdom, Tzipi Hotovely told CNN on Wednesday.

Hamas leader Ismail Haniyeh said in a televised speech Tuesday night that the group was ready if Israel ramped operations up further. "If [Israel] wants to escalate, we are ready for it, and if it wants to stop, we're also ready. If they want to remove their hand over Jerusalem, we're ready," he said.

The militants say their offensive is a response to the actions of Israeli police who fired stun grenades inside the Al-Aqsa Mosque in Jerusalem -- one of the city's holiest sites -- on Monday morning

Hundreds of Palestinians went to hospitals for treatment after ensuing clashes with Israeli police. Video showed Palestinians throwing rocks and stones in sustained battles in and around the mosque with police, who fired rubber coated bullets, as well as stun grenades. The violence was the most serious the city has seen in years.

The chief prosecutor of the International Criminal Court warned Wednesday that possible war crimes were being committed as the conflict escalated.

"I note with great concern the escalation of violence in the West Bank, including East Jerusalem, as well as in and around Gaza, and the possible commission of crimes under the Rome Statute," Fatou Bensouda said in a statement posted on Twitter. "I echo the call from the international community for calm, restraint and a stop to the violence."

The United States has so far blocked approval of a UN Security Council statement on the ongoing violence, which had been proposed by Norway. Two UN diplomats told CNN that the US informed other Council members that it believes a statement could have a negative impact on diplomatic efforts to deescalate.

A spokesperson at the US Mission to the UN said "the United States is engaging constructively to ensure any action by the Security Council is helpful in de-escalating tensions."

Asked about the bloodshed on Wednesday, US President Biden told reporters that he had recently spoken with Netanyahu. He said that his national security and defense staff were "in constant contact" with their Middle Eastern counterparts -- "not just Israelis, but also everyone from the Egyptians to the Saudis to Emiratis," he said.

Mourners react during the funeral of Israeli Arab Khalil Awaad and his daughter Nadine, 16, in the village of Dahmash near the Israeli city of Lod, on Wednesday.

Meanwhile, there is growing concern over emerging violence in a number of towns in Israel with a majority Arab population. On Wednesday, Israel declared a state of emergency in the central city of Lod after a second night of clashes between Jewish and Arab communities, which saw a synagogue set on fire.

A CNN team driving through Lod early Wednesday saw streets strewn with rocks and burnt out cars on the side of roads. "We have lost control of the city and the streets," Lod Mayor Yair Revivo told Israel's Channel 12 News.

In a sign of how seriously Israel's leadership takes the unrest in Lod, Prime Minister Benjamin Netanyahu made a visit to the city at 2 a.m. Wednesday morning to talk to local leaders.

Israel also said Wednesday it was sending reinforcements to mixed cities to quell the violence.