Russia fired cruise missiles at cities across Ukraine during rush hour on Monday morning, killing civilians and knocking out power and heat, in what President Vladimir Putin declared to be revenge for Ukrainian attacks including on a bridge to Crimea.

The missiles tore into busy intersections, parks and tourist sites in the centre of downtown Kyiv with an intensity not seen even when Russian forces attempted to capture the capital early in the war.

Explosions were also reported in Lviv, Ternopil and Zhytomyr in western Ukraine, Dnipro and Kremenchuk in central Ukraine, Zaporizhzhia in the south and Kharkiv in the east.

In a televised address, Putin said he had ordered“massive” long-range strikes against Ukrainian energy, command and communication targets, using missiles fired from air, sea and land, in response to what he described as terrorist attacks, including Saturday's explosion at the Kerch Strait bridge.

"The Kyiv regime, with its actions, has put itself on the same level as international terrorist organisations. With the most odious groups. To leave such acts without a response is simply impossible,” Putin said.

The Kremlin was humiliated on Saturday when an explosion damaged the only bridge over the Kerch Strait linking Ukraine's Crimea peninsula, annexed by Moscow in 2014, to Russia proper. Ukraine has not claimed responsibility for the blast on the bridge but has celebrated it.

Ukrainian President Volodymyr Zelenskiy said Monday's rush hour attacks were deliberately timed to kill people as well as to knock out Ukraine's power grid. His prime minister said 11 major infrastructure targets were hit in eight regions, leaving swaths of the country with no power, water or heat.

In Kyiv, the body of a man in jeans lay in a street at a major intersection, surrounded by flaming cars. In a park, a soldier cut through the clothes of a woman who lay in the grass to try to treat her wounds. Two other women were bleeding nearby.

'They are trying to destroy us'

A huge crater gaped next to a children's playground in a central Kyiv park. The remains of an apparent missile were buried, smoking in the mud.

More volleys of missiles struck the capital again later in the morning. Pedestrians huddled for shelter at the entrance of Metro stations and inside parking garages.

Germany said a building housing its consulate in Kyiv had been hit in Monday's strike, though it had not been used since the war started on Feb. 24.

The European Union condemned Monday's “barbaric and cowardly attacks” on Ukraine.

By mid-morning, Ukraine's defence ministry said Russia had fired 81 cruise missiles, and Ukraine's air defences had shot down 43 of them. Police said at least five people had been killed and 12 wounded in Kyiv.

Security camera footage showed shrapnel and flames engulfing a glass-bottomed footbridge across a wooded valley in the city centre, one of Kyiv's most popular tourist sites. One pedestrian ran away from the blast. Reuters later saw a huge crater beneath the bridge, which was damaged but remained standing.

"They are trying to destroy us and wipe us off the face of the earth,” Zelenskiy said on the Telegram messaging app.“The air raid sirens do not subside throughout Ukraine.”

Zelenskiy later filmed a video message on a mobile phone on an empty central Kyiv street. He said the strikes had two main targets: energy infrastructure and people.

"Such a time and such targets were specially chosen to cause as much damage as possible,” he said.

Prime Minister Denys Shmygal promised to restore utilities as quickly as possible. Officials reported that power was down in Ukraine's second largest city Kharkiv and nearby Poltava.

Foreign Minister Dmytro Kuleba tweeted:“Putin's only tactic is terror on peaceful Ukrainian cities, but he will not break Ukraine down. This is also his response to all appeasers who want to talk with him about peace: Putin is a terrorist who talks with missiles.”

Olena Somyk, 41, sheltered with her 6-year-old daughter, Daria, in an underground garage where hundreds of other people waited for the all-clear. She had reached Kyiv earlier in the war after fleeing through Russia and across Europe from the Russian-occupied southern city of Kherson.

"Really, I think they did this because they are bastards,” said Somyk. Putin, she said, “is a small angry man, so we don't know what more to expect”.

Belarus escalation

In another sign of possible escalation, Putin's closest ally, President Alexander Lukashenko of Belarus, said on Monday he had ordered troops to deploy jointly with Russian forces near Ukraine, which he accused of planning attacks on Belarus with its Western backers.

"Their owners are pushing them to start a war against Belarus to drag us there,” he said, citing no evidence. Lukashenko allowed Belarus to be used as a staging ground for Russia early in the war but has not sent his troops to fight.

Commentators on Russian television have increasingly been calling for massive retaliation against Ukraine, with the military leadership facing public criticism for the first time as Russian forces have been beaten back on the battlefield.

Ramzan Kadyrov, the staunchly pro-Kremlin leader of Russia's Chechnya region who had demanded in recent days that military commanders be sacked, hailed Monday's attacks:“Now I am 100% satisfied with how the special military operation is being conducted.”

"We warned you Zelensky, that Russia hasn't even got started yet, so stop complaining ... and run! Run away without looking back to the West,” he wrote.

The Kerch Bridge, which Putin personally opened, is a major supply route for Russian forces in southern Ukraine and a symbol of Russia's control of Crimea.

Russia has faced major setbacks on the battlefield since the start of September, with Ukrainian forces bursting through front lines and recapturing territory. Putin responded to the losses by ordering a mobilisation of hundreds of thousands of reservists, proclaiming the annexation of occupied territory and threatening repeatedly to use nuclear weapons.