London City airport has been closed over the discovery of Second World War explosives in the dock sited alongside the runway.
All flight operations for 12 February have been cancelled.
NOTAM information for London City states that the airport has been "zero-rated" as a result of "operational disruption".
"Any aircraft must ensure [the] runway is open before taking off," it adds.
The ordnance was discovered in the King George V dock, which runs alongside the airport's single runway, on 11 February.
London City's chief executive Robert Sinclair says an exclusion zone has been put in place.
"I urge any passengers due to fly today not to come to the airport and to contact their airline for further information," he adds.
The airport handles some 4.5 million passengers annually.
Sinclair says the airport is "co-operating fully" with law enforcement and the Royal Navy and "working hard to safely remove the device".
Eastern London was heavily bombed in the Second World War and the discovery of unexploded bombs has previously forced closure of the airport.