US President Joe Biden has given the green light for Ukraine to use long-range missiles supplied by the US to strike Russia,
BBC reports.
A US official has confirmed the move, a major change of US policy, to the BBC's US partner CBS.
For months, Ukraine's President Volodymyr Zelensky has been urging that the restrictions on the missiles, known as ATACMS, be lifted - allowing Kyiv to strike outside its own borders.
On Sunday he reacted to the reports, saying "such things are not announced, missiles speak for themselves".
Russian President Vladimir Putin has previously warned Western nations against such a move, saying it would represent the Nato military alliance's "direct participation" in the Ukraine war.
He was yet to comment on Sunday's reports although other senior Kremlin politicians described it as a serious escalation.
Washington’s decision on ATACMS is couched in terms of being limited to the defence of Ukrainian forces inside Russia's Kursk region, where Kyiv launched a surprise incursion in August.
In effect, the Biden administration is telling Ukraine that it will support its efforts to hold onto the small chunk of Russian territory it currently occupies, as a powerful bargaining chip for any possible negotiations in the future.
Serhiy Kuzan, chairman of the Kyiv-based Ukrainian Security and Cooperation Centre, told the BBC that Joe Biden's decision was "very important" to the country.
“It’s not something that will change the course of the war, but I think it will make our forces more equal.”
