A WWII bomb was defused in Hong Kong on Thursday after forcing a busy commercial district into lockdown.

Roads were closed and thousands evacuated from surrounding shops, hotels and offices.

It was the second time within a week that an American bomb dropped during WWII had been discovered at a harborfront construction site in Wan Chai.

Police sealed off parts of the district after a worker found the device on Wednesday morning, with 4,000 people evacuated and ferry services across Victoria Harbour suspended as bomb disposal experts worked through the night.