4 Explosions lit up Kyiv night sky: Russian advance slowing

Conflicts - Ukraine soldiers at a defence position. EPA via BBC News

Four major explosions have lit up the night sky in Kyiv, captured by witnesses on video.

It is unclear what the targets of the attack were, or whether there were casualties.

It comes as Russia intensifies its attacks on key Ukrainian cities - with fighting raging for a seventh day in the north, east and south.

Russian and Belarusian athletes have been banned from the Winter Paralympics.

The United Nations says one million refugees have now fled Ukraine to neighbouring countries.

The International Criminal Court opens an investigation into potential war crimes by Russia in Ukraine.

Hundreds of people are feared dead in the southern port of Mariupol following hours of sustained shelling, city's deputy mayor says. – BBC News summery

Meanwhile, Little progress has been made in the last three days by the long convoy of Russian forces approaching Kyiv, according to a British military intelligence assessment.

The main body of the military column, which is approaching the capital from its north, "remains over 30km from the centre of the city having been delayed by staunch Ukrainian resistance, mechanical breakdown and congestion".

Russia has for the first time said it sustained heavy military casualties during its attack on Ukraine, with 498 troops killed and a further 1,597 injured. Ukraine has claimed that far more Russian troops have been killed. The BBC cannot independently verify these claims. - BBC

The defence ministry update also adds that the cities of Kharkiv, Chernihiv and Mariupol remain under Ukrainian control.