The plan was apparently developed and ready for activation

Government statement

On Friday, the Singapore Government released a videotape that helped the authorities capture the suspected militants.

The tape was found in the rubble of a house in Afghanistan belonging to a leader of al-Qaeda - the terror network blamed for the attacks on the United States.

Plans

A government statement said the suspects had worked out two plans which were "ready for activation".

One plan was to blow up a shuttle bus carrying US personnel between a naval base and a local underground station.

Another was to bomb US naval vessels off Singapore.

The PM said the hunt would continue

The statement said eight of the men had received weapons training in al-Qaeda camps in Afghanistan.

The prime minister said more could be at large.

"We cannot say that we have discovered everything. We must work on the assumption that there may be more cells."

The 13 men are being held under the country's controversial internal security act, which allows for detention without trial for up to two years.

The government has said the suspected militants belonged to a group called Jemaah Islamiah, which it said was part of a larger network with cells in Malaysia and Indonesia.

Tape link

The tape which led to the arrests features a man describing how easy it was to carry explosives on a bicycle without arousing suspicion.

The man - identified as Hashim Bin Abas - was among 15 Islamic militant suspects arrested last month. Two have since been released.

He is filmed in Singapore with the camera zooming in on alleged targets, including a commuter train station.

Then it focuses on a bicycle bay at the station, where bicycles are shown with boxes mounted in the back.

"These are the same type of boxes which we intend to use," Bin Abas says, apparently referring to where explosives would be hidden.

He also mentions making use of a drainage hole in the curb of a street adjacent to a nearby temple and across from the train station.