Ukraine’s army is trying to repel a full-scale Russian invasion, with fierce battles taking place close to the capital Kyiv.
Fighting is raging at an airfield on the outskirts of the city, and it could become a springboard for the Russian army into Kyiv if its troops seize it.
The Russian assault is being fought on several fronts after it attacked from the east, north and south on Thursday.
Kyiv has been hit by blasts, and at least one block of flats was damaged.
There are also reports of gunfire inside the city and on its northern outskirts, amid Ukrainian government warnings that “saboteurs” may already be operating inside the city.
Footage circulating on social media on Friday appears to show tanks driving down streets in the northern Obolon district. The Ministry of Defence has appealed to the district’s residents to “inform us of troop movements, to make Molotov cocktails [firebombs] and neutralise the enemy” on its Facebook page.
They [the Russians] say that civilian objects are not targets. It is a lie,” Ukraine’s President Volodymyr Zelensky said in a video released early on Friday. “The reality is that they don’t see a difference in which areas they target.”
Ukraine says at least 137 people – civilians and soldiers – have been killed, with UN estimates suggesting more than 100,000 people have already fled from their homes. Overnight, at least 1,000 Ukrainians arrived by train in Poland’s south-eastern city of Przemysl alone.
British Defence Minister Ben Wallace said the UK estimated Russia had lost 450 personnel since Moscow launched the offensive in the early hours of Thursday morning.
President Vladimir Putin – who declared war in a dramatic televised address – has threatened any country attempting to interfere with “consequences you have never seen”.