World leaders have been paying tribute to the Queen after her death at 96 - with US President Joe Biden saying she was "more than a monarch. She defined an era".
US President Joe Biden released a statement in which he said "in a world of constant change, she was a steadying presence and a source of comfort and pride for generations of Britons".
The president said she was a "stateswoman of unmatched dignity and constancy" who "helped make our relationship special".
Mr Biden said the Queen "charmed us with her wit, moved us with her kindness, and generously shared with us her wisdom" when he and the first lady visited last year.
"Her legacy will loom large in the pages of British history, and in the story of our world," he added.
Canadian Prime Minister Justin Trudeau tweeted: "It was with the heaviest of hearts that we learned of the passing of Canada's longest-reigning Sovereign, Her Majesty Queen Elizabeth II.
"She was a constant presence in our lives - and her service to Canadians will forever remain an important part of our
Speaking to reporters, he added that the Queen was "one of my favourite people in the world".
"I will miss her so," he said.
French President Emmanuel Macron posted on social media: "Her Majesty Queen Elizabeth II embodied the British nation's continuity and unity for over 70 years.
"I remember her as a friend of France, a kind-hearted queen who has left a lasting impression on her country and her century."
Russian President Vladimir Putin said he extended his condolences to Britain for the "irreparable loss" of the Queen.
Pope Francis said he was deeply saddened by the Queen's death and offered his condolences to her family including her successor, King Charles.
The pontiff said in a telegram to the new monarch: "I willingly join all who mourn her loss in praying for the late Queen's eternal rest, and in paying tribute to her life of unstinting service to the good of the Nation and the Commonwealth."
Australian Prime Minister Anthony Albanese tweeted a statement paying tribute to the Queen's "historic reign and a long life devoted to duty, family, faith and service".
"This is a loss we all feel, for few have known a world without Queen Elizabeth II. In her seven remarkable decades on the throne, Her Majesty was a rare and reassuring constant amidst rapid change.
"Through the noise and tumult of the years, she embodied an exhibited a timeless decency and an enduring calm."
Former US president Barack Obama released a lengthy statement saying that the Queen had "captivated the world".
"Michelle and I were lucky enough to come to know Her Majesty, and she meant a great deal to us," he said.
"Back when we were just beginning to navigate life as President and First Lady, she welcomed us to the world stage with open arms and extraordinary generosity.
"Time and again, we were struck by her warmth, the way she put people at ease, and how she brought her considerable humour and charm to moments of great pomp and circumstance.
"Like so many, Michelle and I are grateful to have witnessed Her Majesty's dedicated leadership, and we are awed by her legacy of tireless, dignified public service. Our thoughts are with her family and the people of the United Kingdom at this difficult time."
Former US president Donald Trump said he and wife Melania were "deeply saddened".
"She will always be remembered for her faithfulness to her country and her unwavering devotion to her fellow countrymen and women," he said on his social media platform Truth Social.
"Melania and I will always cherish our time together with the Queen, and never forget Her Majesty's generous friendship, great wisdom, and wonderful sense of humour. What a grand and beautiful lady she was-there was nobody like her!"
German Chancellor Olaf Scholz said: "We mourn Queen Elizabeth II. She was a role model and inspiration for millions, including here in Germany.
"Her commitment to German-British reconciliation after the horrors of World War II will not be forgotten. She will be missed, not least her wonderful sense of humour."
Indian Prime Minister Narendra Modi said: "Her Majesty Queen Elizabeth II will be remembered as a stalwart of our times.
"She provided inspiring leadership to her nation and people. She personified dignity and decency in public life.
"Pained by her demise. My thoughts are with her family and people of UK in this sad hour."
EU Commission chief Ursula von der Leyen said on Twitter that the Queen had "witnessed war and reconciliation in Europe and beyond, and deep transformations of our planet and societies".
"She was a beacon of continuity throughout these changes, never ceasing to display a calmness and dedication that gave strength to many. May she rest in peace."