LONDON — After an announcement earlier in the day that doctors were concerned for the health of Britain's Queen Elizabeth II, Buckingham Palace said Thursday that she had died. She was 96.
The palace said the King and the Queen Consort — Prince Charles, the Duke of Cornwall, and his wife, Camilla, the Duchess of Cornwall — will remain at Balmoral Castle, the queen's royal residence in Scotland, on Thursday evening and will return to London on Friday.
Immediate family members have been informed and traveled to Balmoral.
"Following further evaluation this morning, The Queen's doctors are concerned for Her Majesty's health and have recommended she remain under medical supervision," Buckingham Palace had said in a statement earlier in the day.
The queen's other three children, Princess Anne, Prince Andrew and Prince Edward, as well as her grandson Prince William, the Duke of Cambridge, were also at the palace.
Prince Harry, the Duke of Sussex, was on his way. His wife, Meghan, the Duchess of Sussex, is not traveling with him but potentially could join Harry in Scotland at a later date, according to a spokesperson.
Princess Kate, the Duchess of Cambridge, has remained in Windsor as Prince George, Princess Charlotte and Prince Louis are on their first full day at their new school, Kensington Palace said.
The queen, who was Britain's longest-reigning monarch, had reportedly been suffering from deteriorating health for the past several months, with doctors citing ongoing "episodic mobility problems."
On Tuesday, the queen broke with tradition and appointed her 15th prime minister from Balmoral rather than traveling to Buckingham Palace, as is typical. She was also forced to cancel a planned virtual meeting with senior ministers after being advised to rest by her doctors.
Britain's new prime minister, Liz Truss, who met with the queen Tuesday, said her thoughts were with her and her family.
"My thoughts — and the thoughts of people across our United Kingdom — are with Her Majesty The Queen and her family at this time," she said earlier Thursday.
Keir Starmer, leader of Britain's opposition Labour Party, said he was deeply concerned about the news of the queen's health.
"Along with the rest of the country, I am deeply worried by the news from Buckingham Palace this afternoon," he said earlier Thursday in a statement.
Earlier in the day, Scotland's first minister, Nicola Sturgeon, said she was "profoundly concerned" and Wales' first minister, Mark Drakeford, sent his best wishes on behalf of the people of Wales.
The news of the queen's ill health came as members of Parliament were gathered in the House of Commons to hear details of the government's plan to help households and businesses with rising energy costs.
Cabinet minister Nadhim Zahawi was seen entering the chamber during the meeting and speaking urgently to Truss. Notes about the developing situation were also passed to the Commons speaker and the Labour leader.
Elizabeth had been queen of Britain and more than a dozen other countries since 1952, when she acceded to the throne at aged 25.
Her reign saw 15 prime ministers, from Sir Winston Churchill to Liz Truss, and 14 U.S. presidents.
Earlier this year, she marked her 70th year on the throne with a series of Platinum Jubilee celebrations spanning four days. The queen only traveled to Buckingham Palace twice during that time, first for her Trooping the Colour balcony appearance and then for a finale after the pageant.
Her husband Philip, the longest-serving royal consort in history, died last year at aged 99.