Police sealed off part of a busy area of central Hong Kong on Wednesday after an unexploded bomb was found during construction work in the Asian financial centre.
A police spokesman said explosive ordinance disposal officers were deployed to the scene in the city's Wan Chai district.
He was not able to give any more details.
Police diverted traffic, while shops and offices in surrounding towers were closed for the rest of the day and ferry services from a nearby pier were halted.
It is the second time in less than a week that a bomb has been unearthed at the site of a cross-harbour commuter rail link.
On Sunday, police defused a 1,000lb (454kg) bomb believed to be a US-made device dropped by a plane during the Second World War, when the then-British colony was the scene of fighting between Allied and Japanese occupation forces.