Biggest World War II 'earthquake' bomb found in Poland explodes while being defused

The biggest World War II bomb ever found in Poland exploded underwater on Tuesday as navy divers tried to defuse it. No one was injured in the accident.

More than 750 people had been evacuated from the area near the Piast Canal outside the town of Swinoujscie where the Tallboy bomb used by Britain's Royal Air Force (RAF) was found.

Swinoujscie was part of Germany and called Swinemunde at the time of the bombardment.

The blast was reportedly felt in parts of the port city of Swinoujscie.

It weighed nearly 5,400 kg, including 2,400 kg of explosive.

Naval forces used a remote-controlled device to try to "deflagrate" the bomb - a technique that if successful burns the explosive charge without causing detonation.

"The deflagration process turned into detonation. The object can be considered as neutralised, it will not pose any more threat," Second-Lieutenant Grzegorz Lewandowski, the spokesman of the 8th Coastal Defense Flotilla, was quoted as saying by state-run news agency PAP.

"All mine divers were outside the danger zone."

Swinoujscie contains a liquefied natural gas (LNG) terminal but a spokesman for the town's mayor told PAP no one was injured and no infrastructure had been damaged.

The 19ft, 12,000lb device, designed by British aeronautical engineer Barnes Wallace, was nicknamed 'Tallboy' and also known as an 'earthquake bomb'.

The 5.4-tonne bomb was found last year in September beneath a waterway leading to the port of Szczecin during work to deepen the passage.

The Piast Canal connects the Baltic Sea with the Oder River on Poland's border with Germany. The bomb was dropped by the RAF in 1945 in an attack on the German cruiser Lutzow.

(With Reuters inputs)