The main separatist leader in eastern Ukraine was killed in a bombing at a cafe in the centre of rebel hub Donetsk on Friday, becoming the most prominent victim from the Moscow-backed side in the four-year conflict.
Russia swiftly blamed Ukraine for the killing of businessman-turned-warlord Alexander Zakharchenko, who is the highest level victim in a series of killings of separatist politicians and commanders since the conflict began in 2014.
"The head of the DNR (Donetsk People's Republic), Alexander Zakharchenko, has died as the result of a terrorist attack today," Zakharchenko's spokeswoman Alena Volynets told AFP.
The official website of the DNR said an explosion went off in the "Separ" cafe at 1430 GMT, which it said injured three others.
An AFP journalist at the scene said police had cordoned off the block where the blast occurred.
Zakharchenko, 42, who commanded rebels fighting Ukrainian government forces in the mining and industrial town of Donetsk, was elected first president of the unrecognised republic in 2014.
He said at the time his ambition was to build "a new state".
A "deputy chairman of the government" Dmitry Trapeznikov has been appointed acting head of the self-proclaimed republic during an emergency meeting, the separatist news agency reported.
Separatist forces were put on alert as the DNR authorities launched a special operation aimed at finding those responsible for the blast that has also left three people wounded including one high-ranking rebel official.
- Mutual accusations -
Moscow and the rebel regions blame the murders on Kiev, which counters that the crimes are tied to internal strife and Russia's desire to control the territory.
Russian President Vladimir Putin sent his condolences to Zakharchenko's family and friends.
In a letter published on the Kremlin website, Putin said the separatist leader was "a true people's leader, a brave and resolute man... in a difficult time for his homeland, he stood up in its defence, assumed a huge personal responsibility, and led the people".
Putin said he expected to see the killers brought to justice.
DNR official Denis Pushilin said Kiev was behind Zakharchenko's death, in comments carried by the separatist news agency.
"This is a further aggression from the Ukraine side... Donetsk will avenge this crime," he said.
Russian foreign ministry spokeswoman also said that it is likely that "the Kiev regime is behind the murder," Russian news agencies reported.
Ukrainian security service (SBU) however blamed the killing on rival separatists or Moscow. "Zakharchenko's death could be the result of internal conflicts among the fighters," SBU official Igor Guskov told Ukraine's 112 channel.
More than 10,000 people have been killed since the rebel insurgency broke out in the eastern Donetsk and Lugansk regions in April 2014 following Russia's annexation of Crimea from Ukraine.
Kiev and its Western allies accuse Russia of funnelling troops and arms across the border.
Moscow has denied the allegations despite evidence it has been involved in the fighting and gives open political support to the rebels.
Among other leading figures who have been killed outside the battlefield are commanders Mikhail Tolstykh, Alexei Mozgovoy, Alexander Bednov and Arsen Pavlov.
Last year, the chief of police of the so-called Lugansk People's Republic Oleg Anashchenko was killed when his car blew up in Lugansk.