British Prime Minister Keir Starmer and United States President Joe Biden will discuss in Washington on Friday whether to let Ukraine fire US long-range missiles inside Russia as President Vladimir Putin warns that such move means the West is at war with his country.

British media reported that Biden, who is wary of provoking a nuclear conflict, was ready to let Kyiv deploy British and French missiles using US technology but not US-made missiles themselves.

The talks come at a time when Biden is on his way out of office and November’s US election is a toss-up between Democrat Kamala Harris and Republican Donald Trump.

Washington currently authorizes Ukraine to only hit Russian targets in the occupied parts of Ukraine and some in Russian border regions directly related to Moscow’s combat operations.

But on Thursday, Putin, said, “This would in a significant way change the very nature of the conflict. It would mean that NATO (North Atlantic Treaty Organization) countries, the US, European countries, are at war with Russia.”

Starmer’s visit — his second to Washington since his Labor party stormed to victory in July after 14 years — is also aimed at papering over differences on the war in Gaza.

Starmer’s government last week announced restrictions on some weapons to Israel, voicing concern that they could be used to violate international humanitarian law.

The White House has declined to criticize Britain’s decision, but Politico reported that Washington had asked London what it would take to change its decision — with the answer being a ceasefire in Gaza.