A bodyguard who was travelling with Britain’s foreign secretary has been suspended from duties after he reportedly left a loaded gun on a plane. British media reported Saturday that the police protection officer travelling with Foreign Secretary Dominic Raab on a visit to the United States left the pistol on a plane at London’s Heathrow Airport on Friday. A cleaner found the weapon.

London’s Metropolitan Police said the force was aware of “the incident on a flight into the UK on Friday” and “taking this matter extremely seriously.”

“The officer involved has since been removed from operational duties whilst an internal investigation into the circumstances is taking place,” the police department said Saturday in a statement.

A similar incident took place in February when the bodyguard for former Prime Minister David Cameron left his gun in the bathroom on a British Airways flight. It was reportedly found by a passenger, who handed it to flight attendants.

Raab visited Washington this week to speak with US Secretary of State Mike Pompeo and other officials about Brexit.