Hanoi  - Construction workers building a luxury hotel in downtown Hanoi had to halt their work temporarily when they uncovered two unexploded bombs dropped by the US Air Force during the Vietnam War, a military official said Monday.

The bombs were discovered Friday by workers digging the foundations for a four-star hotel across the street from Hanoi's main railway station, which was heavily targeted by US bombers.

"We moved the bombs out of the construction site on Saturday," said Lieutenant Colonel Tran Dinh Oai, commanding officer of the local Army Steering Committee.

Oai said the construction site was sealed off while the bombs were transported to a rifle range, where they were detonated with explosives.

Local media reported that the bombs, each 60 centimetres long, were discovered 6 metres underground. Workers at the construction site said they were shrapnel bombs, but Oai said he believed they were rockets.

Construction has resumed on the SAS Hanoi Royal hotel, a joint venture between the Hanoi Tourism Corp and Sweden's SIH Investment Ltd.

The incident was the second time this year that Hanoi's building boom has led to the discovery of unexploded ordnance. On January 2, workers laying fiber-optic cables found a bomb under Tran Hung Dao Street in the city's downtown shopping district.

According to the United Nations, 104,000 Vietnamese have been killed by bombs, landmines and artillery shells since the end of the war in 1975.

Vietnam's bomb-disposal agency estimated that 800,000 tons of bombs, landmines and artillery are still buried in uncleared areas totaling 6.6 million hectares. At the current rate of clearance, it would take Vietnam 440 years to clear these areas. (dpa)