Ukraine has used British-supplied Storm Shadow missiles to strike Russian territory for the first time, a report said Wednesday, citing a Western official who spoke on condition of anonymity.

A spokesperson for Prime Minister Keir Starmer told Blomberg that his office would not be commenting on reports or operational matters.

Britain had previously said Ukraine could use Storm Shadow cruise missiles within Ukrainian territory but the government has been pressing the United States for permission to allow their use to strike targets inside Russia for several months.

U.S. President Joe Biden changed its policy to allow Ukraine to use U.S.-made weapons to strike deep into Russia this week.

Vladimir Putin signed a decree Tuesday lowering the threshold for using nuclear weapons, a move that the White House, U.K. and European Union condemned as "irresponsible."

He has used nuclear rhetoric throughout the conflict but has grown increasingly belligerent since last year, pulling out of a nuclear test ban treaty and a key arms reduction agreement with the U.S.