HONG KONG, Feb. 1 (Xinhua) -- Another World War II bomb was disposed of at a construction site in Hong Kong by the police on Thursday, which triggered a mass evacuation of over 4,000 people.

This is the second time within a week that an unexploded wartime bomb found in the same location in the northern part of Wan Chai, where a railway link was under construction.

The bomb, unearthed on Wednesday and weighing about 450 kg, was confirmed to be an American-made explosive and believed to have been dropped from a U.S. warplane during World War II, same as the one discovered on Saturday. Both took the police at least one day to finish up the disposal works.

"Because of the rain yesterday, the working conditions were not good. And the location made it extremely difficult to be able to access it," Bomb Disposal Officer of the police Alick McWhirter said.

It was extremely dangerous for the officers who engaged in the operations, he added.

The bomb disposal expert described the disposal operations as "dirty, difficult and dangerous."

A 200-meter cordon was set up by the police when burning the explosives inside the bomb. Police officers were there to remind people to keep clear of the cordon line.

Superintendent Kwok Mei-sum, Wan Chai District divisional police commander, said that they received a report of the bomb at 11 a.m. local time (0300 GMT) on Wednesday and started the evacuation at 2 p.m.

More than 4,000 people were evacuated from the residential buildings, hotels and office buildings nearby. Miss Cheng, whose office was cordoned off, told Xinhua that a notice was issued by her employer on Wednesday, asking employees to leave before 5:30 p.m., about an hour earlier than the official off-work time.

She said there was no chaos when leaving the office and she later received another notice from her company about further arrangement of going back to office.

Renaissance Hong Kong Harbor View Hotel, which was nearby the bomb, was given notice from the police that some of their rooms would be affected. They immediately suspended services of those rooms and helped arrange affected guests to check in to other hotels.

Home Affairs Department of the Hong Kong Special Administrative Region government opened Wan Chai Activities Center on Queen's Road East, Wan Chai, as a temporary shelter for people who might become homeless due to the road closure.

In a spacious resting area, mattresses, drinking water and instant noodles were provided for people who had registered to use the service.

Mr. Kwong, an officer from the department, said the center usually closes at 10 p.m. but it operated round the clock when it became a temporary shelter, adding that the center received a total of four people between Wednesday and Thursday.

The police expressed gratitude towards the public for their cooperation at a press briefing after the bomb was safely removed.