HONG KONG — Thousands of Hong Kong residents were evacuated overnight so experts could defuse a large U.S.-made bomb from World War II uncovered at a construction site in Quarry Bay, a busy residential and business district.

Police said the bomb measured 1.5 meters (nearly 5 feet) in length and weighed about 1,000 pounds (450 kilograms). It was discovered by construction workers late Friday.

“We have confirmed this object to be a bomb dating back to World War II,” said police official Andy Chan Tin-Chu. Due to “the exceptionally high risks associated with its disposal,” authorities urged around 1,900 households — involving some 6,000 people — to evacuate swiftly.

The defusing operation lasted through the night and was completed around 11:30 a.m. Saturday without injuries.

Unexploded ordnance from World War II is still occasionally found in Hong Kong.

The city, occupied by Japan during the war, was targeted by U.S. and Allied air raids aiming to disrupt Japanese military and shipping operations. — Agencies