Joe Biden has said the UK was fortunate to have had the Queen for 70 years, adding: “We all were, the world’s better for her.”
The US president and First Lady Jill visited Westminster Hall to pay their respects to the Queen lying in state ahead of her funeral on Monday.
Mr Biden said it was an honour to meet the Queen and added that the late monarch reminded him of his mother.
Asked why the monarch reminded him of his mother, he said: “Just because of the way she touched when she leaned over. The way she had that look, like, ‘are you okay? Anything I can do for you? What do you need?’ and then also ‘make sure you do what you are supposed to do’.”
Please use Chrome browser for a more accessible video player
He said: “To all the people of England, all the people of the United Kingdom, our hearts go out to you and you were fortunate to have had her for 70 years.
“We all were. The world is better for her.”
Mr Biden and the first lady were joined by the US ambassador to the UK, Jane Hartley, when they arrived to see the Queen lying in state shortly before 5pm on Sunday.
They were greeted at Westminster Hall by Black Rod Sarah Clarke.
Large crowds were gathered behind barricades near Buckingham Palace and Parliament Square Garden ready to take photos of the motorcade.
Some children were sitting on their parents’ shoulders trying to get a view.
Security was tight and road crossings were closed ahead of the visit as rumours spread through the crowd about the imminent arrival of the president and his entourage.
Air Force One touched down at Stansted Airport just before 10pm on Saturday evening.
The president had been due to meet Prime Minister Liz Truss on Sunday but the talks were cancelled on Saturday.
A “full bilateral meeting” was scheduled for Wednesday when the leaders are set to be in New York for the UN General Assembly.