Vyacheslav Volodin, 58, former deputy head of the Kremlin, was reportedly meeting separatist officials in Donetsk when he was targeted.

The uber-loyalist hardline politician is the speaker of the Russian parliament - and has previously been tipped as a possible Putin successor.

According to Russian newspaper Kommersant, missiles hit the private office of Denis Pushilin, the leader of the pro-Putin puppet state Donetsk People’s Republic.

Ukraine also struck the nearby meeting room where Volodin, once a vice-premier of Russia, and top Moscow parliamentary aides had been meeting separatist officials.

The office was destroyed in the strike just "minutes" after they left.

Pictures from the scene show significant damage to the upper floors of the building.

Shells hit the facade of the building and "partially destroyed the right wing and the top floor", the Donetsk News Agency reports.

Six people were injured in the attack after a missile also hit a nearby hotel.

Local reports said three people were killed, including an 18-year-old man.

Volodin and his pals were said to be meeting separatist officials to discuss integrating the Donetsk region - legally part of Ukraine - into Russia.

It comes just hours after another top pro-Putin official in occupied Ukraine was killed in a car bomb just days after the daughter of the tyrant's war guru was assassinated.

The blast which killed Ivan Sushko, 40 was captured on CCTV.

Sushko – who was married with a daughter - was an official in occupied Zaporizhzhia region and was killed when an explosion ripped apart his car today. 

He was reportedly taking his adopted daughter to kindergarten when he was targeted - but she was left unharmed.

Sushko was head of the Mykhailivka - military-civilian administration - in the region which is home to Europe’s largest nuclear plant at Zaporizhzhia. 

“An explosive device had been placed under his car seat,” said senior Russian official in the occupied region, Vladimir Rogov.

Putin loyalist Rogov said the attack was carried out by “saboteurs” in the region, and vowed to track them  he downclaimed that Ukraine was attacking Russian-backed officials who "help improve the lives of ordinary people

The dead man's wife Tatyana accused "Ukrainian Nazis" of carrying out the car bombing.