Russia pounded Kyiv with a large missile and drone attack early on Sunday, killing two people and wounding 56, authorities said, after President Vladimir Putin threatened retaliation for strikes in Russian-occupied eastern Ukraine.

Multiple rounds of loud explosions were heard in the Ukrainian capital throughout the early hours of the morning, AFP journalists said.

“Tonight Kyiv region is once again enduring a mass enemy attack with strike drones, cruise missiles and ballistic missiles,” said Mykola Kalashnyk, the head of the regional military administration.

The blasts caused a residential building near the government district to shake, while dozens of people took shelter in an underground metro station in the city center, AFP reporters said.

Residents were instructed to stay in shelters, as city authorities warned fires had broken out and Mayor Vitali Klitschko said two people had been killed and at least 56 wounded, 30 of them in hospitals.