In a statement released on Thursday, the palace said: "The Queen died peacefully at Balmoral this afternoon", prompting an outpouring of condolences from around the globe.
Mr Biden and his wife Jill said the Queen, who had met 14 American presidents, “led always with grace, an unwavering commitment to duty and the incomparable power of her example”.
The pair said they first met the Queen in 1982, and when they made their first overseas trip to the UK as president and first lady in 2021 “she charmed us with her wit, moved us with her kindness, and generously shared with us her wisdom”.
Mr Biden said she "endured the dangers and deprivations of a world war alongside the British people" and rallied the country through the devastation of the Covid pandemic.
The pair added: “Queen Elizabeth II was a stateswoman of unmatched dignity and constancy who deepened the bedrock alliance between the United Kingdom and the United States. She helped make our relationship special.”
Following the announcement from Buckingham Palace, Mr Trudeau said "she was a constant presence in our lives", adding that "Canadians will always remember and cherish Her Majesty’s wisdom, compassion, and warmth."
"Our thoughts are with the members of the royal family during this most difficult time," he tweeted.
Ukraine’s President Volodymyr Zelenskyy tweeted: “It is with deep sadness that we learned of the death of Her Majesty Queen Elizabeth II. “On behalf of the people, we extend sincere condolences to the @RoyalFamily, the entire United Kingdom and the Commonwealth over this irreparable loss. Our thoughts and prayers are with you.”
France's President Emmanuel Macron described the Queen as a "kind-hearted" person who has left an enduring impression on "her country and her century".
He said she was a friend of France.
Echoing these sentiments, German Chancellor Olaf Scholz said the Queen was a "role model and inspiration for millions" of people, as he praised her commitment to German-British reconciliation after the "horrors of World War II". "She will be missed, not least her wonderful humour," he added.
Portugal’s Prime Minister António Costa was another world leader who expressed sadness following the passing of Her Majesty. “Her 70-year long reign has marked British history since the Second World War," he tweeted. “My sincere condolences to the royal family and to the people of the United Kingdom.”
Nato Secretary General Jens Stoltenberg also shared his deep sadness over the passing of Her Majesty. “Over more than 70 years, she exemplified selfless leadership and public service. My deepest condolences to the royal family, to our #NATO Allies the United Kingdom and Canada, and to the people of the Commonwealth,” he tweeted.
European Commission President Ursula von der Leyen, meanwhile, offered her “heartfelt condolences” to the royal family and the British people following the news of the death. “She was the world’s longest-serving head of state and one of the most respected personalities worldwide," she tweeted.
Brazilian President Jair Bolsonaro said the country would be holding three days of official mourning in honour of the Queen. He described the monarch as not just the Queen of England but a “Queen to all of us”.
Mr Bolsonaro added that she was an “extraordinary and unique woman, whose example of leadership, humility and love for (her) homeland will continue to inspire us and the whole world until the end of time”.
Narendra Modi, the prime minister of India, wrote on Twitter that the Queen will go down in history "as a stalwart of our times".
"She personified dignity and decency in public life. Pained by her demise," he wrote in a tribute.
Also praising Her Majesty's commitment to public duties, former US President Barack Obama said he and wife Michelle had been “awed” by the Queen’s “legacy of tireless, dignified public service”. In a statement posted on Twitter, he said Her Majesty had “captivated the world”, adding: “Her Majesty was just 25 years old when she took on the enormous task of helming one of the world’s great democracies. “In the decades that followed, she would go on to make the role of Queen her own – with a reign defined by grace, elegance, and a tireless work ethic, defying the odds and expectations placed on women of her generation.”
Bill Clinton, the former US president from 1993 to 2001, said himself and Hilary Clinton were mourning the passing of The Queen.
"We will always be grateful for the kindness she showed us through the years, particularly during our visits to Buckingham Palace in 1995 and 2000, and for all she did to deepen the special relationship", he said in a statement posted to Twitter.
Adding to the tributes, Irish Taoiseach Micheal Martin conveyed his deepest sympathy following the death of the Queen, saying it represented the "end of an era". Mr Martin said: “The Queen’s reign was one of historic duration, immense consequence and a focus of respect and admiration around the world. “Her dedication to duty and public service were self-evident and her wisdom and experience truly unique. “The Queen’s passing is indeed the end of an era."
Dutch Prime Minister Mark Rutte said the Netherlands remember the Queen “with the deepest respect”. “During her especially long reign, she was a beacon of calm and stability for her country and the world, even at moments of the greatest historical upheaval… Today our thoughts are first and foremost with her children and grandchildren.”
Prime Minister of Finland Sanna Marin sent her “deepest condolences the royal family, people of the United Kingdom and the Commonwealth”, while President of the United Arab Emirates Sheikh Mohamed bin Zayed called the Queen “a close friend”.
The condolences came after Buckingham Palace issued a statement earlier on Thursday that the Queen was under medical supervision at Balmoral after doctors became concerned for her health.
The Queen’s four children – and two of her grandsons – travelled to Balmoral, the Queen’s Scottish Highlands home, to be by her side.
Her reign spanned 15 prime ministers - starting with Winston Churchill - and included encounters with countless world leaders.
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