Russia’s death toll is “considerably higher” than figures released by the Kremlin, the UK said today.
A statement released by the Ministry of Defence sought to debunk official reports coming from Russia.
Yesterday, Russia claimed some 498 of its troops had died and another 1,597 had been wounded over the first week of their invasion of Ukraine.
But a UK intelligence update on the situation said: “The Russian defence ministry has been forced to admit that 498 Russian soldiers have already been killed and 1,597 wounded in Putin’s war.
“The actual number of those killed and wounded will almost certainly be considerably higher and will continue to rise.”
A military adviser to Ukrainian president Volodymyr Zelenskyy claimed some 6,000 Russian servicemen had been killed and hundreds had been taken prisoner, including senior officers.
However, it is near impossible to verify figures due to the rapidly changing situation.
The UK’s statement said the main body of the large Russian column advancing on Kyiv remains over 30km from the city centre after it was delayed by “staunch” Ukrainian resistance, mechanical breakdown and congestion.
“The column has made little discernible progress in over three days,” the Ministry of Defence added.
It comes after major explosions were captured on camera by witnesses in Kyiv where residents are braced for a siege.
Russia has intensified its attacks on Ukrainian cities - as fighting rages on across the country.
Ukraine’s second-largest city Kharkiv is reeling from intense strikes while the port city of Kherson is said to be under the control of Putin’s forces.
The UK’s security minister Damian Hinds said he was was “desperately concerned” and Russia posed a danger to “wider Europe and the world”.
“This is a ruthless invading force,” he told Sky News.
“When it comes to tactics and military strategy, I’m not going to second guess Vladimir Putin and what he might be thinking, what might be in his head.
“But we do know that this is a ruthless force, an extremely dangerous [force] obviously imminently right now for Ukraine, but actually dangerous for wider Europe and the world.”
The United Nations said a million refugees have now fled to neighbouring countries.
Meanwhile, the International Criminal Court is opening an investigation into potential war crimes by Russia.