LONDON — President Biden met with 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.
Mr. Biden arrived at 10 Downing Street on Monday morning, his first visit to the prime minister’s office as president, and was greeted with a warm handshake by Mr. Sunak.
“We’re very privileged and fortunate to have you here,” Mr. Sunak said.
“It’s good to be back,” Mr. Biden said. Mr. Biden and Mr. 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, Mr. 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 United States and Britain are among Ukraine’s most stalwart supporters, but the two leaders have differed on the question of whether and how quickly Ukraine should be able to join NATO.
Mr. Sunak said last month that Ukraine’s “rightful place is in NATO,” although he has not called for Ukraine to be given a “road map” to membership in the trans-Atlantic military alliance.
Mr. Biden has been more hesitant, and in an interview aired on Sunday he offered his most definitive statement to date that Ukraine was not ready for membership, saying it was “premature” to begin the process to allow Ukraine to join the alliance in the middle of a war.
The meeting also comes after Mr. Biden made what he called the “very difficult decision” to send cluster munitions to Ukraine, a move at odds with several of America’s closest allies. Britain was one of the nations that signed onto a convention prohibiting the sale or use of such weapons, which are known to cause grievous injury to civilians. Mr. Sunak reiterated over the weekend that Britain “discourages” the use of the munitions.
Mr. Sullivan said this week that America’s allies did not oppose Mr. Biden’s decision, and that Ukraine needed the weapons to protect its citizens.
In an interview with CNN’s Fareed Zakaria, Mr. Biden said that he did not “think there is unanimity in NATO about whether or not to bring Ukraine into the NATO family now,” and that the process could happen only after a peace agreement with Russia was in place. Referring to the alliance’s commitment to mutual defense, Mr. Biden said: “If the war is going on, then we’re all in war.”
He added that there would be “other qualifications that need to be met, including democratization,” for Ukraine to be considered for membership.
Later on Monday, Mr. Biden met with King Charles III at Windsor Castle, near London, where the two discussed clean-energy investment and efforts to fight climate change in developing nations. Those are issues that Charles has been warning about since the 1970s and that Mr. Biden has made a central focus of his presidency.
Mr. Biden did not attend the coronation of Charles in May, instead the first lady, Jill Biden, and their granddaughter Finnegan went. When he called the king to send his regrets and offer congratulations, Charles invited the president to visit Britain, setting the stage for the Monday meeting that American officials are calling a “mini state visit.”
The logistics for Mr. Biden’s trip have not been without some static. The White House initially questioned the need for a stop at 10 Downing Street with Mr. Sunak, according to an official familiar with the planning, since the two men would meet at the NATO summit a day later. For Mr. Sunak, however, a handshake with the president in front of his residence is politically valuable, and the White House ultimately agreed to it.
Katie Rogers and Mark Landler contributed reporting.
