Explosions rocked cities across Ukraine on Monday, hours after Russian President Vladimir Putin accused Ukraine of attacking the bridge linking Russia and Crimea.
In the capital, Kyiv, the blasts struck the Shevchenskivskyi district, mayor Vitali Klitschko said, a large area that includes the historic old town as well as several government offices.
Thick smoke billowed over central Kyiv after explosions were heard around 8am local time. Air raid sirens sounded for more than an hour before the blasts.
Gen Valeriy Zaluzhny said on social media that Russia had carried out massive missile and air strikes using attack drones.
About 40 missiles were shot down by Ukraine's air defences, he added.
“Ukraine is under missile attack. There is information about strikes in many cities of our country,” Kyrylo Tymoshenko, deputy head of the president's office, said on social media, calling on the population to “stay in shelters.”
Aid organisations paused their operations in Ukraine on Monday following the attacks.
The International Committee of the Red Cross said it temporarily halted its work in Ukraine for “security reasons,” while the Norwegian Refugee Council also said that it had halted its aid operations there until it is safe to resume.
President Volodymyr Zelenskyy said there were dead and wounded from the blasts, as he accused Russia of trying to wipe his country “off the face of the earth.”
“The air-raid sirens do not subside throughout Ukraine. There are missiles hitting. Unfortunately, there are dead and wounded,” Mr Zelenskyy said on the Telegram messaging app.
The strikes, which were made including Iran-made drones, were timed to inflict the greatest possible losses, he said.
“They want panic and chaos, they want to destroy our energy system,” Mr Zelenskyy said in a video post that showed him outside his presidential office.
“The second target is people. Such a time and such targets were specially chosen to cause as much damage as possible.”
It comes a day after Russian President Vladimir Putin blamed Ukraine for the destruction of a key bridge connecting Russia to Crimea, annexed by Moscow in 2014.
Mr Putin said the attack on the bridge was “an act of terrorism aimed at destroying critically important civilian infrastructure”.
“This was devised, carried out and ordered by the Ukrainian special services,” he said in a video on the Kremlin's Telegram channel.
Justin Crump, the chief executive of an intelligence consultancy Sibylline, said the explosions marked the first time Kyiv has been hit in months.
“I think there was a feeling increasingly in recent weeks following Ukrainian successes that Russia wouldn’t stand off forever and would start to target the city once again,” he told Radio 4’s Today programme on Monday.
“The threat has always been to target decision making centres in Kyiv, Russia’s own words about this, no one has been quite sure what they mean by that. But there is a chance these strikes, timed during rush hour on a Monday morning, were there to strike exactly the sort of centres Russia has been talking about.
“An obvious target they might have chosen is the intelligence service headquarters, given they blamed them publicly for the attack on the bridge, which I think would also be commensurate with some of the locations we have seen. I stress though that information coming out of Ukraine is limited.”
The Russian transport ministry, quoted by RIA news agency, said the bridge had reopened, and nearly 1,500 people and 162 heavy cargoes had travelled by ferry across the Kerch Strait since the explosion.
Mr Crump said while the bridge was now back in limited operation, Russia was taking some “engineering risks” with it.
He said Mr Putin originally opened the bridge, which was built by “one of his best friends”. And he was pictured driving the first lorry convoy over it in 2018.
“It was a sign of Russian pride in the recapture of Crimea and obviously it’s a blow. And a very significant piece of infrastructure for them.
“I think it really counts, because it shows the conflict is reaching back into Russia in ways that Russia perhaps considered unimaginable, certainly earlier.
“So there is no surprise they are trying to bring it back to Ukraine more with a degree of anger and fury, not only in Kyiv but in other cities this morning. ”
Mr Putin's anger over the damage to the bridge also coincided with growing concerns that Moscow could resort to nuclear weapons. He has repeatedly cautioned the West that any attack on Russia could provoke a nuclear response.
Ukraine has not claimed responsibility for the bridge blast but senior Russian officials demanded a swift response from the Kremlin before a meeting of Mr Putin's security council on Monday.
The capital has witnessed relative calm in recent months, with fighting focused on the regions just north of Crimea, including Zaporizhzhia, where six missiles were launched overnight on Saturday from Russian-occupied areas.
The Russian shelling destroyed an apartment building in Zaporizhzhia, killing at least one person and injuring five, according to city officials.
The pre-dawn strikes in Zaporizhzhia were the third such attack against the region in four days. A further strike on an apartment in the city on Sunday killed at least 13 and injured 87, including 10 children, according to Ukrainian officials.
Russian aircraft launched at least 12 missiles in Sunday's attack, partially destroying a nine-storey apartment block, levelling five other residential buildings and damaging many more, the governor of Zaporizhzhia, Oleksandr Starukh, said.