The mayor’s office in a key eastern Ukrainian city controlled by pro-Kremlin separatists was struck by rockets on Sunday 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.
Three neighbouring parked cars were reported to have burned out as a result of the hit by RIA Novosti and local media.
Kiev did not immediately take responsibility for the incident or make any comments.
Without presenting any supporting evidence, Kremlin-backed separatist authorities have previously claimed that Ukraine has carried out multiple attacks on residential and infrastructure targets in the seized regions using long-range Himars rockets from the US.
The attacks happened a day after two men from an ex-Soviet country opened fire on volunteer troops while they were practising their aim at a firing range used by the Russian military close to Ukraine, killing 11 and injuring 15 before they were also killed. The fatalities were reported by the Russian Defense Ministry, which described the incident as a terrorist strike.
The occurrences occur as President Vladimir Putin hastily mobilises Russian soldiers in Ukraine in response to a string of battlefield losses following his invasion in February. Thousands of people fled Russia as a result of the call-up, which also led to protests.
On Saturday, another accusation was made against Moscow by a Washington-based research tank, which said that "large, forced deportations of Ukrainians" were probably ethnic cleansing.
The Institute for the Study of War cited remarks made this week by Russian authorities, according to which "several thousand" youngsters from a southern region taken by Moscow had been housed in rest homes and children's camps in Russia in the midst of a still-active Ukrainian counteroffensive.
The initial comments made by Marat Khusnullin, the deputy prime minister of Russia, were published by the official RIA Novosti news agency on Friday.
The Institute also asserted that, in violation of international humanitarian law, Russian authorities "may additionally be engaging in a wider campaign of ethnic cleansing by depopulating Ukrainian territory through deportations and repopulating Ukrainian towns with imported Russian residents."
In the past, Russian authorities have publicly acknowledged adopting out children from Ukraine's Russian-controlled regions who they said were orphans, possibly in violation of a major international agreement on the prevention of genocide.
The 1948 Genocide Convention defines genocide as "forcibly transferring children of the (targeted) group to another group" and was approved by more than 140 states, including Ukraine and Russia.
The Ukrainian military also claimed that pro-Kremlin troops had violated international humanitarian law by evicting citizens from their houses in occupied territory so that they could make room for officers.
In a routine Facebook update, the General Staff of the Ukrainian Armed Forces stated that the evictions were taking place in the eastern Luhansk area, in the Russian-controlled city of Rubizhne, where Kyiv has been waging a counteroffensive. It did not back up its assertion with any supporting data.
