Ukraine says it has killed 15,000 of Russia's troops since its invasion began.
The country's military branch, the General Staff of the Ukrainian Armed Forces, said on Monday that a large proportion of Russia's total invading troops are dead.
Russia started its invasion on 24 February with an estimated force of 190,000 troops.
Ukraine's military also claimed that it had taken out a number of the enemy's armoury and artillery, the Kyiv Independent reported.
Watch: Kyiv mayor Vitali Klitschko says he cries 'every day' at destruction Putin has caused
Officials said they had destroyed 1,535 armoured personnel carriers, 498 tanks, 969 vehicles, 240 pieces of artillery, 45 anti-aircraft systems, 80 rocket launcher systems, 97 planes and 121 helicopters.
Meanwhile, eight people were reported dead on Monday following Russian shelling on a residential area and shopping centre in the Ukrainian capital of Kyiv.
In the port city of Mariupol, which has been under heavy Russian bombardment, an estimated 300,000 people are trapped without food, water or power.
Ukraine ignored a demand from Russia to give up the city by 5am Moscow time on Monday, saying the invaders' pledge to temporarily halt its attack could not be trusted.
It accused Russia of trying to starve out its citizens in the city.
Ukrainian MP Inna Sovsun also claimed its citizens in Mariupol are being abducted and deported to "distant parts of Russia" to work in conditions akin to slave labour.
Speaking to Times Radio, she said Russia was following “the logic of Nazi Germany”.
“From what we know from the city mayor and the city council, is they are taking Ukrainian citizens,” she said.
The UK's foreign secretary, Liz Truss, said she was "appalled" by the claims.
On Sunday, a Russian bomb destroyed an art school in Mariupol where 400 people had taken shelter, with rescuers searching for people possibly trapped under the rubble.
Only days before the shelling, there was a separate attack on a theatre in the city where more than 1,000 people were said to have been hiding.
Truss said: “I am appalled by Russian atrocities in Mariupol, including attacks on schools sheltering civilians and the abduction and deportation of Ukrainians."
She said Russian president Vladimir Putin is "resorting to desperate measures as he is not achieving his objectives".
On Monday, health secretary Sajid Javid said the UK could welcome hundreds of thousands of Ukrainian refugees in the coming weeks.
After the government’s Homes for Ukraine scheme opened at the weekend, Javid said those arriving in the UK would get all the support they needed.
Some 10,200 visas have been issued under the Ukraine family scheme as of 4pm on Sunday, the Home Office said on Monday.
A total of 31,500 applications have been submitted so far.
Javid said 150,000 people had expressed an interest in hosting refugees through the Homes for Ukraine programme.
Watch: Ukrainian orphans head to UK after escaping war