London City Airport canceled all flights Monday after an unexploded World War II-era bomb surfaced nearby in River Thames, according to multiple reports.

Officials discovered the 1,100-pound, 5-foot long bomb in the sand Sunday at the George V Dock in North Woolwich, London during planned maintenance work near the airport. 

Authorities said bomb specialists and the Royal Navy have confirmed the device is a German undetonated explosive and are working on removing it safely. 

"The first stage of the removal operation is to free the shell from the silt so that it can be floated for removal," police said in a statement, according to the Associated Press.

The Metropolitan Police established a 700-foot exclusion zone where all properties inside have been ordered to evacuate. Those looking to travel the highlighted streets were urged to seek alternative routes. Officers have been assisting residents in the affected area reach safe ground.

However, moving the device may be tricky due to uncontrollable factors and could take another 24 hours, police said in a statement, according to BBC News.

"The timing of removal is dependent on the tides, however, at this stage we estimate that the removal of the device from location will be completed by tomorrow morning," the statement read. 

London City Airport apologized to travelers unable to board any of its 261 flights affected by the bomb. Robert Sinclair, CEO of the airport, released a statement regarding the incident. Docklands Light Railway, which services the airport has also been shut down.

"I recognize this is causing inconvenience for our passengers, and in particular some of our local residents," Sinclair said, according to BBC. "The airport is cooperating fully with the Met Police and Royal Navy and working hard to safely remove the device and resolve the situation as quickly as possible."

Undetonated bombs are common in parts of London. In August 2015, construction workers discovered a 500-pound German bomb in East London. The London Fire Brigade uncovered nine unexploded WWII bombs in the capital during that year.