THE MAYOR’S OFFICE in a key eastern Ukrainian city controlled by pro-Kremlin separatists was struck by rockets this morning, Russian state agencies reported.

There were no immediate reports of casualties.

According to news agency RIA Novosti, the municipal building in Donetsk was seriously damaged by the attack, which local separatist authorities blamed on Ukraine.

Photos circulating on social media showed plumes of smoke swirling around the building, rows of blown-out windows and a partially collapsed ceiling.

RIA Novosti and local media also reported that three cars parked nearby had burnt out as a result of the strike.

Kyiv did not immediately claim responsibility or comment on the attack.

Kremlin-backed separatist authorities have previously accused Ukraine of numerous strikes on infrastructure and residential targets in the occupied territories, often employing the US-supplied long-range Himars rockets, without providing corroborating information.

The strikes came a day after two men from a former Soviet republic fired at volunteer soldiers during target practice at a Russian military firing range near Ukraine, killing 11 and wounding 15 before being killed themselves. The Russian Defence Ministry, which reported the killings, called the incident a terrorist attack.

The incidents come amid a hasty mobilisation ordered by President Vladimir Putin to beef up Russian forces in Ukraine amid a series of battlefield setbacks following his February invasion. The call-up triggered protests and caused hundreds of thousands to flee Russia.

Also on Saturday, a Washington-based think tank accused Moscow of conducting “massive, forced deportations of Ukrainians” which it said are likely to amount to ethnic cleansing.

In its regular online update, the Institute for the Study of War referred to statements made this week by Russian authorities, which claimed that “several thousand” children from a southern region occupied by Moscow had been placed in rest homes and children’s camps in Russia amid an ongoing Ukrainian counter-offensive.

The original remarks by Russia’s deputy prime minister, Marat Khusnullin, were reported by the state RIA Novosti agency on Friday.