• Members of Britain's royal family land in Scotland as queen's health is of concern to nation, reports AP

Britain's Queen Elizabeth II is under medical supervision on Thursday at her Balmoral Castle residence in Scotland after doctors became concerned for her health, Buckingham Palace said.

Her son and heir, Prince Charles, his wife Camilla - Duchess of Cornwall, and grandson Prince William travelled to Balmoral to be with her, according to their Clarence House and Kensington Palace offices. The 96-year-old monarch is said to be "comfortable" at Balmoral, where she has been for her summer break.

"Following further evaluation this morning, the Queen's doctors are concerned for Her Majesty's health and have recommended she remain under medical supervision, the Buckingham Palace statement said, according to PTI in London.

"The Queen remains comfortable and at Balmoral," it said.

The 96-year-old monarch has been suffering from age-related mobility issues and has cut down her travels, including appointing new Prime Minister Liz Truss in Scotland earlier this week.

The whole country will be deeply concerned by the news from Buckingham Palace this lunchtime, Truss tweeted.

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.

Meanwhile, House of Commons Speaker Sir Lindsay Hoyle interrupted a debate on energy bills in Parliament to update MPs about the Queen's health.

He cut short a speech to say: "I know I speak on behalf of the entire House when I say that we send our best wishes to Her Majesty the Queen and that she and the royal family are in our thoughts and prayers at this moment.

"If there is anything else, we will update the House accordingly."

The Leader of the Opposition, Labour Leader Keir Starmer, tweeted: Along with the rest of the country, I am deeply worried by the news from Buckingham Palace this afternoon.

My thoughts are with Her Majesty The Queen and her family at this time, and I join everyone across the United Kingdom in hoping for her recovery.

According to reports, the Queen had been due to hold the Privy Council meeting of senior government advisers virtually on Wednesday evening but it was decided it would be rearranged.

The details of the queen’s medical condition are not known, though the palace has said in the past that she has problems with mobility. She recovered from a bout with COVID-19 in February, but said later it had left her exhausted, according to New York Times News Service.

In a photo of her and Liz Truss _ whom the queen invited to form a government on Tuesday _ released by the palace, the queen held a walking stick in her left hand.

The queen’s declining health has been a recurring cause of concern for the last few years, forcing her to cancel many public appearances, even solemn events such as her annual commemoration of Britain’s wartime dead.

She has largely retreated to Windsor Castle, her country residence outside London, though this year she kept to her summer habit of decamping for Balmoral, a castle set amid Scotland’s craggy hills and sylvan dales.

During the Platinum Jubilee in June, marking her 70 years on the throne, a smiling monarch appeared on the balcony of Buckingham Palace to watch a parade and a Royal Air Force flyover in her honor. But she skipped most of the rest of the celebrations, including a gala concert held in Queen Victoria Square, in front of the palace.

As the queen has receded from public view, Charles has taken on many of her public duties, including the state opening of Parliament and the conferring of knighthoods. She stopped traveling outside Britain several years ago.

In April 2021, the queen lost her husband of 73 years, Prince Philip, who died a few weeks before his 100th birthday. At Philip’s memorial service, she sat, masked and alone, in a choir stall at St. George’s chapel in Windsor Castle, a poignant symbol of the pandemic’s social distancing restrictions.

Even in her declining state, the queen has been a constant, revered figure in the public life of the country. During the depths of the pandemic, she addressed a socially isolated nation, assuring Britons, in the words of Vera Lynn’s beloved World War II-era song, that “We’ll meet again.”