BANDA ACEH, Indonesia (AFP) - Gunmen fired at the home of two US academics in the Indonesian province of Aceh on Monday, the latest in a string of attacks directed against foreigners in the region, police said.

No one was injured in the attack on the home of Michelle Ahmad and Sarah Willis in the provincial capital Banda Aceh at around 5:45 am (2245 GMT Sunday), police and witnesses said.

"I heard about six gunshots," said Ahmad, who is understood to be teaching English to local students through a fellowship programme with an Acehnese university.

"We woke up and sprawled on the floor. A few minutes later, I called another friend... and we called the police."

Police intelligence chief Bambang Soetjahjo said the motive for the attack was unknown.

He said it was not clear if it was connected to a recent spate of shootings targeting Westerners in the province, a deeply Islamic part of Indonesia which is recovering from a bitter separatist war.

"We do't know the motive and who did it and if it's connected to previous incidents," Soetjahjo said.

Police said two shots hit the house's walls and one hit the roof.

The attack comes less than a week after motorcycle-riding gunmen fired on the home of the European Union's local representative, a British national, in the province.

The representative of the German branch of the Red Cross was badly wounded in a shooting attack earlier this month, forcing the medical relief agency to briefly suspend its operations in Aceh.

No one has claimed responsibility for the shootings.

Police have said the attacks are aimed at creating a climate of fear among foreign workers in the province, on the northern tip of Sumatra island.

"We see this as an effort to terrorise foreign workers until they leave Aceh," said Kamaruddin Abubaka of the Aceh Transitional Committee, which represents former separatist rebels in post-war political developments.

"We can't let the situation in Aceh heat up. We have to protect the peace that we've built with great hardship."

The Australian embassy updated its travel warning for Indonesia on Monday to include the recent shooting of the German, but it did not raise its overall advice to "reconsider your need to travel" to the country.

"We advise you to exercise extreme caution when travelling to Aceh, especially in remote areas or outside Banda Aceh," it said.

"Travellers in Aceh should, where possible, use main roads and avoid travelling at night. Before travelling to Aceh, you should contact Indonesian authorities to determine whether your activities require official approval."

Aceh has experienced sporadic low-level violence, including armed robberies, kidnappings and politically motivated grenade and gun attacks, despite the 2005 end of a three-decade separatist war that claimed around 15,000 lives.

The staunchly Islamic province is home to a large but steadily declining number of international organisations, which arrived to help after the 2004 Asian tsunami killed 168,000 people in Aceh.