HONG KONG -- Police detonated a 400-pound (180-kilogram) pre-World War II bomb Wednesday found by workers at a construction site.

Police said the bomb was found by drainage workers who were dredging at the construction site.

Hong Kong's Cable TV quoted police as saying that they had to explode the device at the site because it was too unstable to move.

Television footage showed police bomb disposal experts carrying out controlled explosions to detonate the bomb. No one was injured in the process.

Weapons were stored in Hong Kong before World War II and the territory was a battleground during the war. Japanese troops invaded Hong Kong and occupied the then-British colony in 1941-1945 after defeating British, Canadian and Hong Kong soldiers in a two-week battle.