Melitopol's new mayor - believed to have been installed by Moscow - has called on the city to "adapt to the new reality" and stop "committing extremist acts".
Galina Danilchenko, a former member of the city council, was announced as the new mayor on local TV on Saturday, according to reports.
It comes days after Ukraine's parliament claimed the previous mayor, Ivan Fedorov, was kidnapped by armed men acting on behalf of the Kremlin.
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Please use Chrome browser for a more accessible video player 0:32 Moment mayor of Melitopol 'abducted'
In a televised statement, Ms Danilchenko said: "Esteemed residents of the town of Melitopol and Melitopol distict…
"Our main task now is to adapt all the mechanisms to the new reality so that we can begin to live in a new way as soon as possible.
"Despite all our efforts, there are still people in the town who try to destabilise the situation, who spur you on to commit extremist acts.
"I do urge you, please, be sensible and do not fall for these provocations.
"I address the deputies, people's representatives of all levels.
"Esteemed deputies - we were elected by the people and our main task is to take care of their wellbeing first of all.
"With this aim, steps are being taken to create a committee of people's deputies. This committee will manage all administrative matters in Melitopol and Melitopol District."
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Image: Ivan Fedorov was mayor of Melitopol before his alleged kidnap. Pic: Ukraine's parliament
The deputy head of Ukraine's presidential office, Kirill Timoshenko, shared a video on the social media site Telegram that appeared to show the moment Mr Fedorov was captured and escorted across a square in the city centre.
Ukrainian President Volodymyr Zelenskyy accused Russia of employing "a new stage of terror" with the alleged kidnapping.
It led to more than 2,000 people taking to streets of the city demanding his release.
Mr Zelenskyy called on Russian forces to heed the calls. "Please hear in Moscow!" he said.
"Another protest against Russian troops' attempts to bring the city to its knees."
He has also spoken to Israeli Prime Minister Naftali Bennett asking him for help in freeing Mr Fedorov.
Melitopol, about 120 miles (190km) west of Mariupol in southeastern Ukraine, has a population of 150,000 and fell under Russian control on 26 February.
Image: Russia has been in control of Melitopol since 26 February
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OfficeChairHero on March 13rd, 2022 at 15:57 UTC »
It's so bizzare that another country can just walk in and be like, "This is your new mayor now."
rarz on March 13rd, 2022 at 14:10 UTC »
Taking that job at this moment seems like a pretty bad career choice.
mattwebb677 on March 13rd, 2022 at 14:04 UTC »
"Despite all our efforts, there are still people in the town who try to destabilise the situation, who spur you on to commit extremist acts.”
That’s true. They are called Russians.