UK military intelligence says Russia's invasion of Ukraine has largely stalled

Russia's invasion of Ukraine has largely stalled on all fronts, with Russian forces suffering heavy losses and making minimal progress on land, sea or air in recent days, British military intelligence said on Thursday.

"Ukrainian resistance remains staunch and well-coordinated," The Ministry of Defence said. "The vast majority of Ukrainian territory, including all major cities, remains in Ukrainian hands." 

Ukraine's besieged leader urged the United States Wednesday to reconsider his plea for a no-fly zone, invoking the terror of the September 11 attacks as he ratcheted up pressure on the White House to move aggressively against the Russian invasion closing in on Kyiv.

More than three weeks into a war that has left hundreds of Ukrainian civilians dead and three million displaced abroad, President Volodymyr Zelensky told the US Congress the conflict was "a terror that Europe has not seen... for 80 years."

"Remember Pearl Harbor, terrible morning of December 7, 1941, when your sky was black from the planes attacking you," he said, recalling the air raid that brought the United States into World War II.

"Remember September 11, a terrible day in 2001 when evil tried to turn your cities, independent territories, in battlefields," he told lawmakers via a video link livestreamed to the nation.

"Our country experienced the same every day."

Reuters contributed to this report.