A leader of Russian-backed separatists in eastern Ukraine, Alexander Zakharchenko, has been killed in an explosion at a cafe in Donetsk city.
"The head of the DNR [Donetsk People's Republic]... has died as the result of a terrorist attack," Zakharchenko's spokeswoman told AFP news agency.
Some observers have attributed previous deaths of rebel leaders in Donetsk to infighting among the rebels, or moves by Moscow to eliminate inconvenient separatist leaders.
Rebel and Russian news reports say the separatists' "finance minister" Alexander Timofeyev was wounded in the blast at the Separ cafe that killed Zakharchenko.
Ukrainians suspected of being behind the blast were arrested nearby, a security source was quoted as saying.
Russian foreign ministry spokeswoman Maria Zakharova said "there is every reason to believe that the Kiev regime is behind the murder".
Moscow denies sending regular troops and heavy weapons to the separatists, but admits that Russian "volunteers" are helping the rebels. »