Russian President Vladimir Putin says Monday's widespread Russian strikes on Ukraine are retaliation for Saturday's attack on a key bridge.
Putin blames the bridge explosion on Ukraine, and threatens more strikes in response to what he calls "terrorist attacks".
The attack on the bridge badly damaged the only link between Russia and occupied Crimea - a key route for military supplies for the war.
Monday's missile strikes on cities across Ukraine, including the capital, Kyiv, mark a significant escalation.
It's the first time Kyiv has been targeted in months; Ukraine says 11 people have been killed across the country.
Meanwhile, the leader of Belarus, Alexander Lukashenko, has ordered his troops to deploy with Russian forces near Ukraine.
He claims Ukraine and Nato are planning to launch an attack on his country, but offered no evidence.
Shock and horror after Russia's wave of strikes across Ukraine
The past few hours have seen wave after wave of explosions, not just here in Kyiv, but all across this vast country, from Lviv in the west to Kharkiv in the east and Odesa in the south.
For those of us who were here when Russia's full-scale invasion began in February, there's an element of déjà vu. We've been told to spend as much time as we can in the basement, as further attacks, using missiles and drones, are expected.
But this is also different. The explosions here in Kyiv are much closer to the centre. Not distant thumps from the suburbs, but loud reverberations close to streets and locations we've come to know well in the past eight months.
It's difficult to tell what is being targeted, but a statement from Ukraine's ministry of culture said museums and the Philharmonic building had been hit.
One video circulating on social media showed a huge crater in a children's playground.
BBC