Canada and the European Union have joined Australia in closing their diplomatic missions in the Philippines indefinitely after receiving information about an "imminent" terror attack.

(The threat) is quite specific and they are Islamic fundamentalists, extremists of the kind we're used to

Alexander Downer, Australian FM

The move came after Australia said it had received a "credible and specific" warning of the attack by Islamic militants on its embassy in the capital Manila within the next few days.

"It is not only location specific, targeting the Australian embassy itself, but also it's time specific," Australian Foreign Minister Alexander Downer told Australian radio.

Earlier this month, the authorities in the Philippines said they had foiled a plot to bomb the US embassy in Manila. This, they said, was hatched by a group allegedly linked to the al-Qaeda network

Fears of new attacks in the region have intensified since the bomb on the Indonesian island of Bali last month which killed nearly 200 people, many of them Australians.

On high alert

Thursday saw armed police and weapons experts closed streets and circled the Australian embassy in Manila, which occupies five floors in a 10-storey office block in the business district of the city.

The EU's diplomatic mission is located in the same building, and the Canadian embassy is three blocks away.

Mr Downer told Australian television that the threat came from "Islamic extremists, fundamentalist people".

Australian diplomatic staff will remain in the Philippines but will work out of an office or hotel elsewhere in the city until the threat has passed.

Both the Australian and Canadian governments urged their citizens to avoid non-essential travel to the Philippines.

The American embassy was also closed on Thursday for the Thanksgiving holiday, but will reopen again on Friday.

The latest alert follows heightened security awareness in Australia, where the government issued a warning last week about a potential threat over the next few months.

Private security guards now patrol the Sydney Opera House, harbour bridge and other significant sites.

Schools re-open

In Indonesia, however, international schools in the capital, Jakarta, re-opened on Thursday following a two-week closure due to terror threats.

Police continue to quiz chief Bali suspect Imam Samudra

The Indonesian police are continuing to quiz the man whom they say masterminded the Bali bombing - Imam Samudra.

One of Imam Samudra's lawyers was reported by Indonesian newspaper Tempo on Wednesday as saying that his client had admitted bombing a church on an island off Singapore on Christmas Eve 2000.

Indonesian police say he has already admitted planning the 12 October Bali bomb attack.

Police also said they have arrested four more men suspected of involvement in the Bali bombing, bringing the total of those in custody to 19.

Officials said four of them - Agus, Amin, Rauf (alias Sam) and Yudi (alias Andri Oktavia) - either surveyed the nightclubs that were hit or were accomplices of Imam Samudra and Amrozi, the other suspect who is said to have admitted involvement in the bombing.

The remaining 13 were detained when weapons or other materials believed to be linked to the attacks were found in their houses, police said.