Vientiane has been spruced up in preparation

Laos' capital, Vientiane, has been beautified in preparation, with women ordered to wear traditional skirts, bars shut down, and traffic restricted.

The US government warned last month that it had information of possible attacks on the Asean forum.

Laos state-run radio said this week that "bad elements" might plot trouble.

"It is the duty of all Laos people to help this meeting go successfully," Vientiane Deputy Governor Boonchan Singhawong was quoted as saying by the Associated Press.

"They have to abide by these [clean-up] measures to make the city look good and beautiful," he said.

Asean member countries Brunei Burma Cambodia Indonesia Laos Malaysia Philippines Singapore Thailand Vietnam

In addition to tightening security, Lao authorities hope the meeting will give them a chance to showcase the country's tourism potential.

The agenda of the meeting - which gathers together foreign ministers from Saturday, and leaders from Monday - includes a free trade accord between South East Asia and China, and an anti-terrorism pact between Asean (Association of South East Asian Nations) and Japan.

Momentum is also reportedly building for participants to break with Asean's tradition of non-interference in other's internal affairs, and press Burma to introduce democracy.

Burma has recently appointed a new prime minister, who is thought to be even more hardline than his predecessor.

But a senior Burmese foreign ministry official, Thaung Tun, told AP he did not think Asean would involve itself in the subject.

"I don't think the Asean would want to discuss internal affairs. Everybody has internal affairs, but you know in every country there are transformations, including Burma," he said.

Possibly to stem criticism at the meeting, Burma released several political prisoners at the weekend, including former student leader Min Ko Naing.

Security is tight for the forum, with manned checkpoints blocking people from entering the capital from the rural and mountainous provinces. Tourists have been told to stay away, after officials said the capital did not have enough hotel rooms.

Laos is the victim of sporadic bomb attacks, which the authorities usually blame on "bad elements".

This is often a reference to the ethnic Hmong people, who fought alongside the US during the Vietnam War, and claim to have suffered discrimination from the Lao authorities ever since.

Asean, which groups 10 Asian countries, is meeting in the Lao capital from 25 to 30 November.