Ukraine is "able and willing" to begin counteroffensives to take back territory after Russia lost more than 10 per cent of its combat force, according to the Pentagon.
It comes as Ukraine says it retook the strategically significant suburb of Makariv, north of Kyiv, and repelled an attack on the coastal city of Mykolaiv, just east of Odesa on the Black Sea.
Ukraine’s military is now trying to push Russia out of Izyum, in the east of the country, while fighting a breakthrough of Russian troops in Mariupol, according to an anonymous US official who briefed reporters on the Pentagon’s latest battle assessment.
Russia, meanwhile, has made no tangible attempt to physically resupply its troops fighting in Ukraine, which has dropped "slightly below" 90 per cent of its original force for the first time, said the US official, quoted by Foreign Policy and USA Today.
Moscow is said to be considering adding more troops and resupplying those that remain out of the 190,000 originally assembled in Belarus and western Russia before crossing the border on 24 February.
There are also claims that some Russian troops have suffered frostbite, while there are also signs Moscow is having trouble refuelling its ships at sea.
"Clearly they did not properly plan for it," the senior defence official was quoted as saying.
The official added that additional troops would be drawn into Ukraine from outside of Russia, with 75 per cent of its battalion tactical group generation capacity already used in Ukraine.
The mercenary Wagner Group, meanwhile, has reportedly entered the war in the eastern Donbas region. A Ukraine counteroffensive in Izyum, south of Kharviv, would aim to stop Russian forces encircling the bulk of its army on the frontlines in the disputed Donbas.
Ukraine’s defence ministry said regaining the Kyiv suburb of Makariv allowed its forces to retake control of a key highway needed the block the encirclement of the city from the northwest.
Russian forces were able to take control of other suburbs in the northwest, including Bucha, Hostomel and Irpin, but were still almost 10 miles from the city’s centre, the defence ministry added.
The closest the Russian advance has come has reportedly been nine miles to the northwest and 19 miles to the east.
While Kyiv is Vladimir Putin’s primary objective, the bulk of his army remains engaged in battle in the south and east of the country, according to US and British officials.
In Mariupol, which has seen some of the fiercest fighting, Russia has begun shelling the city from seven ships in the Sea of Azov, with some of its troops able to enter the city on Tuesday morning.
More than 1,100 civilians who had escaped the besieged city were on their way in a convoy of buses to another city to Mariupol’s northwest, according to the city council.
Russia has also increased its air sorties over the past two days, carrying out as many as 300 in the past 24 hours, and has fired more than 1,100 missiles into Ukraine since the invasion began.
The Associated Press contributed to this report.
