Ukraine and Russia are trading blame for the killing of a top separatist leader in eastern Ukraine.

Aleksandr Zakharchenko, the head of the head of the breakaway separatist entity known as the Donetsk People’s Republic, was killed in an explosion at a cafe in Donetsk on August 31.

Zakharchenko's killing was the latest in a series of violent deaths of separatist officials and commanders in eastern Ukraine, where the Moscow-backed separatists have been fighting Ukrainian forces since 2014 in a war that has killed more than 10,300. Many of the assassinations have been blamed on fellow rebels.

But Russia was quick to blame Kyiv for Zakharchenko's death.

In the latest comments, Russian Foreign Minister Sergei Lavrov said September 1 that the bombing was "Ukraine's provocation ... obviously aimed at derailing the implementation of the Minsk agreements," referring to the September 2014 and February 2015 pacts aimed at resolving the conflict.

It is now "impossible" to talk about planning the next international talks over the conflict, Lavrov said, according to the state-run TASS news agency.

"This is a serious situation that needs to be analyzed," he added.

However, Ukraine’s security service said it believes the attack was the result of a conflict between "terrorists and their Russian sponsors."

"We do not exclude an attempt by the Russian special services to eliminate a rather odious figure who, according to the information we have, was meddlesome for the Russians," the security service was quoted by state media as saying.

The TASS news agency reported on September 1 that Zakharchenko's bodyguard also died as a result of the blast, while a dozen others were injured.

Another separatist figure, Aleksandr Timpfeyev, was injured in the blast, but his condition was reported to have stabilized on September 1.

Dmitry Trapeznikov, the first deputy prime minister, had been named as acting leader.

Zakharchenko, twice wounded in combat, played an important role in the separatists’ military operation from the beginning, taking part in the seizure of the Donetsk regional administration building by those saying they were protesting against the new pro-Western authorities.

The 42-year-old Zakharchenko, a former coalmine electrician who was born in Donetsk in 1976, survived a car bomb explosion in August 2014, and later in the year he was picked as prime minister by the parliament of the self-proclaimed Donestk People’s Republic.

TASS quoted Trapeznikov as telling the Donetsk News Agency that "several suspects" in the blast were detained and in questioning "confirmed the Ukrainian side's involvement in this crime." The Security Service of Ukraine (SBU) has denied any role in the blast.

Plagued By Infighting

The separatist movement has been plagued by infighting, with several leaders fleeing the region after saying they had been subject to threats from former comrades.

In February 2017, separatist commander Mikhail Tolstykh, 36, whose nom de guerre was Givi, died in an explosion in his office in Donetsk.

Another separatist commander -- Arseny Pavlov, known as Motorola -- was killed when a bomb exploded in an elevator in his apartment block in Donetsk in October 2016.

On January 1, 2015, Aleksandr Bednov, a separatist commander in Luhansk, was killed resisting arrest by fellow separatist authorities on charges he ran a torture chamber in the basement of a separatist-held building.

Since April 2014, more than 10,300 people have been killed in fighting between Kyiv's forces and the pro-Russia separatists who control parts of Ukraine's Donetsk and Luhansk regions.

Moscow has denied providing the separatist forces with weapons despite what Kyiv and NATO say is evidence proving that it has done so.

Russia in 2014 also seized and annexed Ukraine's Crimean Peninsula.

The United States and the European Union have condemned Russia's actions in Ukraine and have slapped a series of sanctions against Moscow in response.

Zakharchenko was sworn into office as the head of the so-called Donetsk People's Republic on November 4, 2014.

At one point, Zakharchenko announced plans to create a country called Malorossia -- Little Russia -- encompassing all of Ukraine with its capital in Donetsk.

However, in August 2017, Zakharchenko called off the plan, saying it "was rejected by many" after it was met with derision and criticism in Kyiv and the West and did not receive the Kremlin's support.

With reporting by Reuters, Interfax, and TASS