A government spokesman said: “The president welcomed the Prime Minister’s recent comments on establishing closer relationships with our European counterparts, as well as the UK’s commitment to Aukus.
“They reflected that at a time when we face growing challenges across the world, we are at our strongest when we unite and work together.”
Sir Keir earlier told reporters he wanted to use the trip to improve relations with the EU in days, not months.
He said that was why he had brought along Nick Thomas-Symonds, his Europe minister.
Sir Keir described the timing of the summit as “a really important window of opportunity for me and my team,” adding: “Because we’ve got the Nato summit within a week of the election…we get the opportunity to strengthen our relations with various Nato leaders and others obviously that are there, including EU leaders,” he said.