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

"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 said in a statement.

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

The next in line to the throne, Prince Charles, and his wife Camilla, have arrived at Balmoral to be with the Queen.

The 96-year-old head of state has been dogged by health problems since last October that have left her with difficulties walking and standing. 

(Cover: Britain's Queen Elizabeth II waits in the Drawing Room before receiving Liz Truss for an audience at Balmoral, in Scotland, September 6, 2022. /CFP)