LONDON -- British Prime Minister Boris Johnson was admitted to hospital for tests on Sunday night, 10 days after testing positive for coronavirus, Downing Street said.

Johnson has tested positive for coronavirus on March 27 and is self-isolating in Downing Street, but his symptoms "continue to persist."

The prime minister said he had experienced mild symptoms over the past 24 hours, including a temperature and cough, but would continue to lead the British government.

"On the advice of his doctor, the prime minister has tonight been admitted to hospital for tests," a Downing Street spokeswoman said.

"This is a precautionary step, as the prime minister continues to have persistent symptoms of coronavirus ten days after testing positive for the virus," the spokeswoman said.

"The prime minister thanks NHS (National Health Service) staff for all of their incredible hard work and urges the public to continue to follow the government's advice to stay at home, protect the NHS and save lives."

Sunday's development came after Johnson's pregnant girlfriend, Carrie Symonds, revealed she had been showing "classic signs" of COVID-19, the disease caused by the coronavirus.

On Saturday, Symonds said that she spent the past week in bed with coronavirus symptoms.

Johnson, 55, and Symonds, 32, announced in February that they were expecting their first child together and were engaged to be married.

On Friday, the prime minister said that he was remaining in isolation with mild symptoms of COVID-19, including a raised temperature.

England's Health Secretary Matt Hancock said he had also tested positive last week.

The number of people who have died after contracting the coronavirus in the UK has jumped by 621 in 24 hours, bringing the total number of people who have died in hospital to 4,934 as of 1600 GMT on Saturday, the British Department of Health said.

As of 0800 GMT on Sunday, a total of 195,524 people have been tested in the country, of which 47,806 tested positive.