The Australian government says it has information that terrorists could attack foreign aid workers in the tsunami relief effort in Indonesia.
The Canberra government is advising Australians not to travel to tsunami-ravaged Aceh and other parts of Sumatra and to postpone non-essential trips to the rest of Indonesia because of possible terror attacks.
Australia's Foreign Minister Alexander Downer issued the unprecedented warning Saturday, saying militants in Aceh could be planning to target foreigners.
"There is no standard too low for these people," he said. "To think that they would contemplate attacking aid workers explains to you what sort of people we are dealing with when it comes to the terrorists. People should not go to Aceh without being attached to a registered organization."
The government also raised the threat level in other parts of Indonesia, saying "attacks could occur at any time", anywhere across the vast archipelago. But it did not give specifics.
The Australian military, which deployed 1,000 unarmed personnel to Indonesia in the aftermath of the Indian Ocean tsunami, says it has no plans to upgrade its security in Aceh.
Civilians involved in the humanitarian effort, however, are considered to be far more vulnerable.
Australian diplomats say past atrocities illustrate how dangerous Indonesia has become.
Last September a suicide attack killed 10 people outside the Australian Embassy in Jakarta. Two and a half years ago, bombs on the island of Bali killed 202, including 88 Australians. The radical Islamic organization Jemaah Islamiyah is widely blamed for the Bali attacks.
Aceh Province has its own troubles, suffering a nearly 30-year bloody separatist rebellion.