WASHINGTON — US Secretary of State Antony Blinken has been grounded in Switzerland after his plane had a "critical failure" due to an oxygen leak, officials said.

America's top diplomat was due to return from the World Economic Forum in Davos when the flight issue occurred.

A separate plane was sent to fetch Blinken, as his aides returned to Washington by commercial flight.

Blinken has visited multiple countries since the Israel-Gaza war broke out in October.

The secretary of state and aides boarded the plane in Zurich on Wednesday and were forced to get off after the leak was identified.

He had been scheduled to return to the US aboard a Boeing 737, according to US media reports.

Mechanical issues on the US Air Force passenger planes have been a concern previously on state department trips.

On Blinken's trip to China last summer, his aides provided reporters with visas for an Azerbaijan refueling stop just in case any maintenance issues grounded the aircraft. — BBC