President Joe Biden met Prime Minister Rishi Sunak of Britain on Monday, making a brief stop in London on the eve of a Nato summit where leaders are expected to focus on supporting Ukraine against the Russian invasion.

Biden arrived at 10 Downing Street on Monday, his first visit to the Prime Minister’s office as President, and was greeted with a warm handshake by Sunak. “We’re very privileged and fortunate to have you here,” Sunak said.

“It’s good to be back,” Biden said. Biden and Sunak have met six times in the last six months, but never at 10 Downing Street. The two men met for more than 45 minutes in the building’s courtyard. “We’re moving along in a way that’s positive. But our relationship is rock solid.”

Jake Sullivan, Biden’s national security adviser, told reporters on Air Force One on Sunday that the two leaders would “talk about progress in the war in Ukraine, and, of course, to talk about a range of other issues from China to climate to technology to artificial intelligence”.

Both men are scheduled to attend a two-day summit of Nato leaders beginning on Tuesday in Vilnius, Lithuania. The US and Britain are among Ukraine’s most stalwart supporters, but they have differed on the question of whether and how quickly Ukraine should be able to join Nato.