Britain's King Charles told the U.S. Congress on Tuesday (April 28) that despite an age of uncertainty and conflict in Europe and the Middle East, the U.K. and the U.S. will always be staunch allies united in defending democracy, at a time of deep divisions between the two long-time allies over the war with Iran.

"Whatever our differences, whatever disagreements we may have, we stand united in our commitment to uphold democracy, to protect all our people from harm, and to salute the courage of those who daily risk their lives in the service of our countries," Charles told U.S. lawmakers during a rare speech to a joint meeting of the U.S. Senate and U.S. House of Representatives, and after a prolonged standing ovation at his entrance with Queen Camilla.

Charles' address came on the second day of a four-day state visit to the U.S. during a tense time in relations between the two countries, after U.S. President Donald Trump has repeatedly criticized U.K. Prime Minister Sir Keir Starmer for what Trump says is his lack of help in prosecuting the Iran war.

"I come here today with the highest respect for the United States Congress - this citadel of democracy created to represent the voice of all American people to advance sacred rights and freedoms," the king said.

Charles also said that the same "unyielding resolve" seen after the September 11, 2001 attacks on the United States was "needed for the defense of Ukraine and her most courageous people ... in order to secure a truly just and lasting peace."

He also said the partnership between Europe and America was "more important today than it has ever been."

Trump has said Starmer, who has won some plaudits at home for not joining the Iran offensive, was no Winston Churchill, while he belittled a later offer of military assistance to defend allies in the region.

Before his speech the Charles met with top Republican and Democratic lawmakers after a morning visit to the White House with Camilla that included a closed-door meeting between the king and Trump. The events are part of a visit to the U.S. designed to underscore ties forged between Britain and its former colony over the 250 years since American independence.

The king was only the second British sovereign to address the U.S. Congress. His mother, Queen Elizabeth II, spoke to both houses in 1991.

-Eva Weininger/Reuters