London City Airport has been closed after a World War Two bomb was found in the River Thames nearby.
Flights have been cancelled, with passengers advised not to travel to the airport and to contact their airline.
The bomb was discovered at about 05:00 GMT on Sunday at George V Dock during pre-planned work at the airport in east London, the Met Police said.
Specialist officers and the Royal Navy confirmed the device was explosive and the airport was shut at 22:00.
The Met said it was working with the Royal Navy to remove the device.
“At 22:00 an operational decision was made with the Royal Navy to implement a 214-metre exclusion zone to ensure that the ordnance can be safely dealt with whilst limiting any risk to the public,” a spokesman said.
Airlines using London City Airport include British Airways, Flybe, KLM and Lufthansa, with flights to domestic and European city destinations.
Its largest operator, British Airways, has cancelled the majority of Monday’s departures and arrivals.
Flybe and CityJet have cancelled most morning flights and are warning disruption is likely throughout the day.
Docklands Light Railway services between the airport and Woolwich Arsenal have been suspended and some roads near to the airport are closed.
Last year more than 4.5 million passengers used London City Airport.
A £400m expansion was given the go-ahead by ministers in July 2016, which includes extending the terminal.
Two million more passengers per year will be able to use the airport from 2025, with 30,000 additional flights annually, the airport said.