KYIV (AFP) — Russia fired its biggest-ever aerial barrage at Ukraine early Sunday, killing at least two people and setting the seat of the Ukrainian government in Kyiv ablaze, authorities said.

An Agence France-Presse (AFP) reporter saw the roof of Ukraine's cabinet of ministers in flames and smoke billowing over the capital.

Drone strikes also damaged several high-rise buildings in Kyiv, according to emergency services.

Russia has shown no sign of halting its three-and-a-half-year invasion of Ukraine, pushing hardline demands for ending the war despite efforts by the United States to broker a peace deal.

The barrage came after several European countries, led by France and Britain, pledged Thursday to deploy "reassurance" forces to Ukraine to patrol a peace deal between the warring sides — a demand Moscow has deemed unacceptable.

The attack on Ukraine's cabinet of ministers, a sprawling government complex at the heart of Kyiv, was the first such strike of the war.

An AFP reporter saw helicopters dropping what appeared to be buckets of water over the roof, as emergency services rushed to the scene.

Police cordoned off the area surrounding the building.

"The roof and upper floors were damaged due to an enemy attack. Rescuers are extinguishing the fire," Prime Minister Yulia Svyrydenko said on Telegram.

"We will restore the buildings. But we cannot bring back lost lives. The enemy terrorizes and kills our people every day throughout the country," she said.