Commenting on the desire by some extremists in the region to fight alongside the ruling Islamic group, Mr Lee said they should be given one-way tickets.

"Get there before the Special Forces get to the ground and show me how good you are," Mr Lee said.

Speaking at a university forum on the need for a new national economic strategy, Mr Lee also said the attacks on the US marked the beginning of a new Cold War.

"After only 10 years of the peace dividend [after the collapse of the Soviet Union] when the US prospered and we in Asia benefited, we have now entered another kind of Cold War, a war against terrorism that will take much more time and stamina than the fight against communism," Mr Lee said.

Efforts to destroy Osama bin Laden and his al-Qaeda network would not be easy, Mr Lee said. The new war "consists of elusive targets who hide in any country whose government gives them refuge", he said.

"To track them down and rip up their networks will be a difficult, long, messy and tedious business."

The perpetrators of the US terror attacks were not representatives of Islam, said Mr Lee, adding that "leading Muslim scholars have denounced such acts as un-Islamic".

The Singapore government has shown strong support for the US-led coalition.