A World War II (WWII) bomb has exploded during a defusing process at the bottom of a Baltic Sea shipping canal in Poland.

BBC reported a Polish Navy spokesperson as saying that it was expected that there was a 50-50 chance that the bomb would explode.

No one was harmed when the deflagration process turned into an explosion.

Commonly known as Tallboy or ‘earthquake’ bomb, the unexploded bomb from the WWII was dropped by the Royal Air Force during a raid in 1945.

The bomb was dropped to sink the German cruiser Lutzow. It was reported to have missed the vessel and remained undetected until last year.

It was found during the preparatory work for deepening the Szczecin-Świnoujście fairway.

Ahead of the diffusion process in the shipping canal in the Baltic Sea, approximately 750 residents living near the Swinoujscie port city were evacuated.

The 6m-long and 5.4t bomb was ‘embedded at a depth of 12m and only its nose was sticking out’.

Polish Navy 8th Coastal Defence Flotilla spokesman lieutenant commander Grzegorz Lewandowski said: “The deflagration process turned into detonation.

“The object can be considered neutralised, it will not pose any more threat to the Szczecin-Swinoujscie shipping channel.”

When the bomb exploded, the shockwaves were reported to have been felt in the city.