Joe Biden will be among the world leaders attending the funeral of Queen Elizabeth II, according to reports.
The US president released a statement after the death of the monarch was confirmed on Thursday.
He described Elizabeth II as “a stateswoman of unmatched dignity and constancy,” who deepened the alliance of the two countries.
Details of the funeral are yet to be announced. The new head of state, King Charles III, will address the nation on Friday evening and there will be a service at St Paul's Cathedral.
Mr Biden met the Queen in June 2021 at Windsor Castle. He first met the monarch in 1982 when he travelled to the UK as part of a senate delegation.
The statement added: “Her Majesty Queen Elizabeth II was more than a monarch, she defined an era.
“In a world of constant change, she was a steadying presence and a source of comfort and pride for generations of Britons, including many who have never known their country without her.
“An enduring admiration for Queen Elizabeth II united people across the Commonwealth. The seven decades of her history-making reign bore witness to an age of unprecedented human advancement and the forward march of human dignity.”
Other world leaders have paid tribute.
French president Emmanuel Macron wrote on Twitter: “To you, she was your Queen. To us, she was The Queen. She will be with all of us forever.”
German chancellor Olaf Scholz added: “We mourn the death of Queen Elizabeth II. She was a role model and inspiration for millions, also here in Germany. Her commitment to German-British reconciliation after the horrors of World War II will remain unforgotten. She will be missed, not least her wonderful humour.”