WASHINGTON: President Joe Biden's administration will allow Ukraine to use US-provided weapons to strike deep into Russian territory, three sources familiar with the matter said, in a significant change to Washington's policy in the Ukraine-Russia conflict.

Ukraine plans to conduct its first long-range attacks in the coming days, the sources said, without revealing details due to operational security concerns.

The White House declined to comment.

The move by the United States two months before President-elect Donald Trump takes office on January 20 follows months of requests by Ukrainian President Volodymyr Zelenskiy to allow Ukraine's military to use US weapons to hit Russian military targets far from its border.

The change follows Russia's deployment of North Korean ground troops to supplement its own forces, a development that has caused alarm in Washington and Kyiv.

The first deep strikes are likely to be carried out using ATACMS rockets, which have a range of up to 190 miles (306km), according to the sources.

While some US officials have expressed scepticism that allowing long-range strikes will change the war's overall trajectory, the decision could help Ukraine at a moment when Russian forces are making gains and possibly put Kyiv in a better negotiating position when and if ceasefire talks happen.

It is not clear if Trump will reverse Biden's decision when he takes office. Trump has long criticised the scale of US financial and military aid to Ukraine and has vowed to end the war quickly, without explaining how.

Still, some congressional Republicans have urged Biden to loosen the rules on how Ukraine can use US-provided weapons.

Russia has warned that it would see a move to loosen the limits on Ukraine's use of US weapons as a major escalation.