Ukraine's Defence Ministry said on Friday that over 1,000 Russian soldiers had been killed so far since the ongoing conflict started.
"Russia has not suffered so many casualties during the fighting in any of its armed conflicts since its inception," the ministry said.
Meanwhile, the UN’s refugee agency has said about 100,000 Ukrainians had been displaced, with thousands fleeing to nearby European states, Al Jazeera reports.
Western powers have announced sweeping sanctions on Russia while hundreds of Russians have staged anti-war protests in cities across the country.
Meanwhile, Hungary has said it will open a humanitarian corridor for citizens from third-party countries like Iran or India fleeing Ukraine, letting them in without visas and taking them to the nearest airport which is Debrecen, the Hungarian foreign minister says.
The general staff of the armed forces of Ukraine has said Russia is using the Gomel airfield in Belarus to line up troops to assault Kyiv due to damage to the Hostomel military airport near the capital.
The military department said in a statement on Facebook that Russian forces were also currently advancing on the city from several directions as Ukrainian forces battled around Mariupol in the south and Kharkiv in the northeast of the country.
“In order to intimidate the population of Ukraine, the enemy is increasingly choosing to destroy civilian infrastructure and housing,” it said.
Al Jazeera’s Andrew Simmons, reporting from Kyiv, says the situation there is rapidly “escalating in every respect”.
“That is not just in the air but on the ground as well – there are armoured [Russian] columns heading towards the city,” he said. “There is real anger in the air … and the hatred for [Russian President Vladimir] Putin is palpable.
“Furthermore, there are a number of places in the city where people can get a gun of their choice, particularly an AK47, to defend themselves and that is the policy of the presidency. Zelinsky wants everyone to fight.
“What we are going to find is that when these Russian forces reach the capital there is likely to be fierce resistance. The overall mood is one of horrendous fear of what’s going to happen next.”
Russian Foreign Minister Sergey Lavrov will hold talks with officials from the self-proclaimed Donetsk and Luhansk republics of eastern Ukraine later on Friday in Moscow, his ministry says.
Putin signed decrees on Monday to recognise two breakaway regions as independent statelets, before ordering what he termed a “special military operation” in Ukraine.
Russian-backed separatists in the Donetsk and Luhansk regions – collectively known as the Donbas – broke away from Ukrainian government control in early 2014 and proclaimed themselves independent “people’s republics.”