The sound of explosions rang out in central Kyiv on Monday morning during rush hour as Ukraine's military warned of a massive Russian missile and drone attack following waves of drone attacks in the early hours.

The air force told Ukrainians Russia had 11 TU-95 strategic bombers in the air and confirmed the launch of a number of missiles. Outside the Ukrainian capital, Reuters reporters heard the sound of air defences engaging targets.

Local authorities reported explosions in the northwestern city of Lutsk and said that an apartment block had been damaged and that they were verifying possible casualties.

The Operational Command of the Polish armed forces said on X that Polish and allied aircraft had been activated after Russia launched the attack which also targeted regions in Ukraine's west and near the Polish border.

Ukrainians have been expecting a major Russian missile attack for some time. The U.S. embassy issued a warning last week of an elevated risk of attack around Ukrainian Independence Day, which Ukraine marked on Saturday.

Ukraine has itself stepped up its long-range drone attacks on Russia to try hit back at Moscow, which launched a full-scale invasion of Ukraine in February 2022.

"The desire to destroy our energy will cost the Russians dearly: their infrastructure," Andriy Yermak, President Volodymyr Zelenskiy's chief of staff, said on Telegram, apparently vowing retaliation.

Russia launched two waves of drone attacks earlier on Monday, Ukraine's military said, with initial information showing no damage or casualties.

Up to 10 drones were destroyed on their approach to the city in the region around Kyiv at about 0230 GMT, Serhiy Popko, head of Kyiv's military administration, said on the Telegram messaging app.

There was no immediate comment from Russia. Both Russia and Ukraine deny targeting civilians. Each says its attacks are aimed at destroying infrastructure key to the other's war effort.