Explosions rocked the centre of Kyiv on Monday morning as Russia launched a new air strike on the Ukrainian capital, hours after unleashing dozens of missiles and drones on targets across the country.

Panicked residents, some of whom initially ignored the air raid siren as they ate breakfast in cafes, rushed to take cover when the sky filled with smoke trails and blast clouds, Reuters witnesses said.

Kyiv mayor Vitali Klitschko said there were explosions in the capital's central districts and that emergency services had been dispatched. He urged residents to stay in shelters.

"Emergency services have responded to a call near the centre of the capital. The attack on Kyiv continues. Don't leave the shelters!" he wrote on the Telegram messaging app as residents ran to shelters in metro stations.

Yuriy Ihnat, spokesperson for the Ukrainian Air Force, said the attack had been conducted with ballistic missiles - thought to be Iskanders - and possibly also S-300 and S-400 missiles.

He said he would provide more details later.

There was no immediate reports of major damage.

Klitschko posted a photograph of a large burning lump of metal lying in the middle of a busy road.

The underground metro was heaving with people taking shelter, many of them checking their phones, footage from the Suspilne public broadcaster showed.

The air raid siren blared across Kyiv and the surrounding region after Russia unleashed dozens of missiles and drones on targets across the country in the early hours of Monday.

Many residents at first ignored the air raid alarm until the calm was shattered by a series of loud blasts in the heart of the city. (Reporting by Olena Harmash, Pavel Polityuk, Max Hunder and Dan Peleschuk, Writing by Tom Balmforth; Editing by Timothy Heritage)