A Russian drone has slammed into a block of flats in eastern Kyiv, killing six people and wounding dozens of others, during a wave of strikes throughout the Ukrainian capital.

As emergency workers sifted through the wreckage in the Lisovyi area, one Kyiv resident called Vita described how the drone had pierced the building, exploding on the other side.

Meanwhile, Ukraine stepped up its attacks on Russia's oil infrastructure, with drone strikes on one of its biggest export terminals in Novorossiysk, on the Black Sea coast.

Fire broke out at the Sheskharis oil refinery, and a ship and a block of flats were hit, officials said.

Krasnodar governor Veniamin Kondratyev said three crew members and another man were hurt in the attack which damaged the main oil depot and a container terminal.

Mayor Andrei Kravchenko declared a state of emergency and Reuters reported that oil exports were suspended.

President Volodymyr Zelensky said Ukraine had fired long-range Long Neptune cruise missiles during its attacks on Russia overnight, without specifying what they targeted.

Condemning Russia's overnight attacks as vile and calculated, Zelensky said about 430 drones and 18 missiles had been launched and dozens of high-rise buildings damaged.

This was a deliberately calculated attack aimed at causing maximum harm to people and civilian infrastructure, he stated.

In Kyiv, residential buildings came under attack in practically every district, as the city faced widespread destruction.

Emergency services reported that the drone struck the seventh floor of the residential building, causing floors below to collapse.

Kyiv's energy infrastructure also suffered damage, leaving some buildings without heat.

Officials reported significant casualties, with nine people treated in hospital, including one in critical condition.

Witnesses described how the drone pierced the entire block before exploding, leaving behind a scene of chaos and destruction.