The royal family and world leaders are mourning Queen Elizabeth II, Britain's longest-reigning monarch, who died Thursday at Balmoral Castle at 96.
"The Queen died peacefully at Balmoral this afternoon," Buckingham Palace announced via social media. "The King and The Queen Consort will remain at Balmoral this evening and will return to London tomorrow."
Her eldest son and heir, King Charles III, 73, immediately became king upon her death.
"The death of my beloved Mother, Her Majesty The Queen, is a moment of the greatest sadness for me and all members of my family," the statement reads. "We mourn profoundly the passing of a cherished Sovereign and a much-loved Mother. I know her loss will be deeply felt throughout the country, the Realms and the Commonwealth, and by countless people around the world.
Obituary:Queen Elizabeth II dies at 96; Prince Charles takes the throne as king
"During this period of mourning and change, my family and I will be comforted and sustained by our knowledge of the respect and deep affection in which The Queen was so widely held," he added.
Reactions to news of Elizabeth's death were swift and plentiful, across countries, news channels and social media platforms.
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UK Prime Minister Liz Truss mourns queen days after meeting with her
"The death of her majesty the queen is a huge shock to the nation and the world," Truss said Thursday in a news conference outside of No. 10 Downing St.
"Queen Elizabeth II was the rock on which modern Britain was built," she added. "Britain is a great country because of her."
On Tuesday, the queen presided over the ceremonial handover of power to the new prime minister from Balmoral Castle in Scotland. Truss highlighted how Queen Elizabeth "remained determined to carry out her duties" until her final days.
Joe Biden remembers queen as a 'steadying presence'
In the U.S., President Joe Biden mourned the queen in a lengthy statement, highlighting her many accomplishments and relationships with American leaders throughout history.
"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," the statement read. "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."
Biden added: "In the years ahead, we look forward to continuing a close friendship with The King and The Queen Consort. Today, the thoughts and prayers of people all across the United States are with the people of the United Kingdom and the Commonwealth in their grief. We send our deepest condolences to the Royal Family, who are not only mourning their Queen, but their dear mother, grandmother, and great-grandmother. Her legacy will loom large in the pages of British history, and in the story of our world."
'I remain committed to serving you':Queen Elizabeth II's most memorable, poignant quotes
Sir Elton John, knighted by queen, calls Elizabeth 'huge part of my life'
"Along with the rest of the nation, I am deeply saddened to hear the news of Her Majesty Queen Elizabeth's passing," Elton John tweeted. "She was an inspiring presence to be around and led the country through some of our greatest and darkest moments with grace, decency and a genuine caring warmth. Queen Elizabeth has been a huge part of my life from childhood to this day, and I will miss her dearly."
The queen knighted John, a friend of the late Princess Diana, in 1998. He also joined the Companions of Honour in the queen’s honors list in late 2019 for his services to music and charity. Last year, Prince Charles anointed John as a member of the Order of the Companions of Honour, one of the highest awards that could be bestowed by the queen to citizens in Britain and across the Commonwealth.
'I remain committed to serving you':Queen Elizabeth II's most memorable, poignant quotes
Nancy Pelosi orders flags flown at half-staff, more US leaders react
House Speaker Nancy Pelosi ordered the flags at the U.S. Capitol to be flown at half-staff.
"Melania and I are deeply saddened to learn of the loss of Her Majesty Queen Elizabeth II," former President Donald Trump shared on his social media platform Truth Social. "Together with our family and fellow Americans, we send our sincere condolences to the Royal Family and the people of the United Kingdom during this time of great sorrow and grief. Queen Elizabeth's historic and remarkable reign left a tremendous legacy of peace and prosperity for Great Britain."
Former President Barack Obama and his wife, Michelle Obama, also recalled the queen fondly.
“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,” the Obamas said in a statement. “Time and again, we were struck by her warmth, the way she put people at ease, and how she brought her considerable humor and charm to moments of great pomp and circumstance."
Former presidents Bill Clinton, George W. Bush and Jimmy Carter also issued statements expressing their condolences.
More:From funeral plans to processions, what happens now that Queen Elizabeth II has died?
Justin Trudeau, Volodymyr Zelenskyy, more world leaders speak out
"It was with the heaviest of hearts that we learned of the passing of Canada’s longest-reigning Sovereign, Her Majesty Queen Elizabeth II," Canadian Prime Minister Justin Trudeau tweeted. "She was a constant presence in our lives – and her service to Canadians will forever remain an important part of our country’s history.
"It is with deep sadness that we learned of the death of Her Majesty Queen Elizabeth II," Ukrainian President Volodymyr Zelenskyy tweeted. "On behalf of the people, we extend sincere condolences to the @RoyalFamily, the entire United Kingdom and the Commonwealth over this irreparable loss."
French President Emmanuel Macron tweeted Thursday that the queen "embodied continuity and the unity of the British nation over 70 years. I retain the memory of a friend of France, a queen of hearts who marked as never before her country and her century."
More leaders around the world, including Germany’s foreign minister, Annalena Baerbock, and Italian Premier Mario Draghi expressed their condolences as well.
Helen Mirren, Mick Jagger, Paul McCartney, more celebrities pay tribute
Many celebrities and public figures have taken to social media to express condolences.
Helen Mirren, who won an Oscar for her portrayal of Queen Elizabeth II in the 2006 film "The Queen," wrote on Instagram that she's "proud to be an Elizabethan."
"We mourn a woman, who, with or without the crown, was the epitome of nobility," Mirren added.
Mick Jagger wrote on Instagram that the reign of Queen Elizabeth II was a constant in his life.
"In my childhood I can recall watching her wedding highlights on TV," he wrote. "I remember her as a beautiful young lady, to the much beloved grandmother of the nation. My deepest sympathies are with the Royal family."
Paul McCartney shared a portrait of the late queen on Twitter with the message "God bless Queen Elizabeth II"
"May she rest in peace," he added. "Long live The King."
Ringo Starr wished "peace and love to all the (royal) family" on Twitter.
In a lengthy Instagram post, the band Duran Duran reflected on the late monarch's legacy.
"We will all miss her and are grateful for the incredible service she gave to the people of Great Britain and the countries of the Commonwealth," the band wrote. "We send our deepest condolence to the royal family. Her death brings to an end a long and unique chapter in the history of the United Kingdom and the world."
Cher recalled on Twitter the time she met the queen.
"I Was In Long Line of Ppl Waiting 2 Meet Her,Yet When She Got 2 Me,She Asked Me Pertinent Questions,& Seemed Genuinely Interested In Talking 2 Me," she wrote.
Piers Morgan tweeted: "I can’t even imagine Britain without this Queen. Very unsettling day."
Contributing: Charles Trepany, USA TODAY; The Associated Press