THE leader of the Russia-backed separatists fighting in eastern Ukraine’s Donetsk region was killed on Friday by an explosion at a cafe, the separatists’ news agency said on Friday.

Rebel news agency DAN said the afternoon explosion that killed Alexander Zakharchenko, 42, tore through the cafe in the region’s principal city.

Mr Zakharchenko was prime minister of the self-declared Donetsk People’s Republic, which along with a separatist republic in neighbouring Luhansk, has fought Ukrainian forces since 2014.

The conflict between Kiev and Moscow-backed rebels has killed more than 10,000 people, rattled eastern Europe and plunged relations between the West and Russia to post-Cold War lows.

It followed the ouster of Kremlin-backed president Viktor Yanukovych in February 2014 after massive street protests over the government’s decision to turn its back on closer ties with the European Union.

Moscow responded by annexing Ukraine’s Black Sea peninsula of Crimea in March, with Russian President Vladimir Putin later admitting on television that he plotted the Crimean invasion to “save” the Russian-speaking region.

Kiev and the West say Russia also instigated the eastern uprising and poured arms and troops across the border to bolster the two self-proclaimed rebel republics of Donetsk and Lugansk.

But the Kremlin portrays the war as an internal conflict between an ethnic-Russian minority angered by a “coup” in Kiev and a nationalist government.

A string of assassinations of rebel warlords in the east remain unresolved.

Each of the two republics are seeking full autonomy from the central government and have their own self-proclaimed presidents.

The killing of the rebel leader of Donetsk, Alexander Zakharchenko, in an explosion on Friday, is the most prominent rebel victim in the conflict to date.

The cafe hit by the explosion, named Separ, was separatist-themed and had camouflage netting hanging from its eaves, according to recent photographs.

Mr Zakharchenko became prime minister of the DPR in August 2014.

He is the most prominent rebel victim in the four-year conflict.

An AFP journalist at the scene said police had cordoned off the block where the blast occurred.

Denis Pushilin, the speaker of the separatists’ parliament, blamed Ukrainian forces for the explosion, calling it “the latest aggression from the Ukrainian side,” according to DAN.

A spokeswoman for the Ukrainian Security Service, Elena Gitlyanskaya, said the Ukrainian special services didn’t have any connection to the blast.

Russian-speakers predominate in those regions, and separatist sentiment skyrocketed.

Encouraged by Russia’s annexation of Crimea, which also came after Mr Yanukovych’s ouster, rebel leaders initially hoped their regions would be absorbed by Russia as well.