Kyiv was heavily bombed early Monday, a day after Moscow blamed Ukraine for an attack which seriously damaged the bridge linking Crimea to Russia. The western city of Lviv has also been targeted. There are reports of dead and injured across Ukraine.
The Russian strikes hit several city-centre targets before dawn. These were the first attacks on the Ukrainian capital since June.
There have been "several explosions in the Shevchenkivskyi district -- in the centre of the capital," Kyiv mayor Vitali Klitschko said on social media.
Internet videos show black smoke rising above many areas in the city.
Ambulances have been heard heading towards the bombed parts of Kyiv, but there has been no information on the number of casualties.
Strikes have also hit Lviv in western Ukraine. President Zelensky says there are "dead and wounded across Ukrain".
Strategic bridge badly damaged
The attacks come a day after Moscow blamed Ukraine for the explosion on a bridge linking Crimea to Russia, an attack which left three people dead.
"The authors, perpetrators and sponsors are the Ukrainian secret services," Russian President Vladimir Putin said of Saturday's Crimea bridge bombing, which he described as a "terrorist act".
The lorry believed to have triggered the explosion was registered in Russia.
Putin is to meet his Security Council later Monday.
The bridge blast sparked celebrations from Ukrainians and others on social media.
But Ukrainian President Volodymyr Zelensky, in his nightly address on Saturday, did not directly mention the incident, and officials in Kyiv have made no direct claim of responsibility.
On Saturday, Russia said some road and rail traffic had resumed over the strategic link, a symbol of the Kremlin's 2014 annexation of Crimea.
The 19-kilometre bridge is a vital supply link between Russia and the annexed Crimean peninsula.
