LONDON, England – British Prime Minister Boris Johnson has been moved to the intensive care unit (ICU) of a London hospital after his coronavirus symptoms worsened.

The office of the United Kingdom leader said Monday that Johnson is conscious and does not require ventilation at the moment.

Johnson was admitted to St. Thomas’ Hospital with a persistent cough and fever late Sunday, 10 days after he was diagnosed with COVID-19.

“Over the course of this afternoon, the condition of the Prime Minister has worsened and, on the advice of his medical team, he has been moved to the Intensive Care Unit at the hospital,” Johnson's office said in a statement.

The 55-year-old leader had been quarantined in his Downing St. residence since being diagnosed with COVID-19 on March 26 — the first known head of government to fall ill with the virus.

Johnson has asked Foreign Secretary Dominic Raab to deputize for him.