More than 200 people were also injured in Aceh's remote, mountainous interior when the strong 6.1-magnitude quake struck on Tuesday, flattening buildings and triggering landslides.

The quake, which struck at a shallow depth of just 10 kilometres (six miles), has sparked panic in the natural disaster-prone region where more than 170,000 people were killed by the quake-triggered tsunami of 2004.

In Blang Mancung village, Central Aceh district, at least six children were killed when a mosque collapsed during a Koran reading session.

Subhan Sahara, head of the district's disaster agency, previously said a further 14 children were trapped in the collapse. But on Wednesday he said rescuers had not yet found any more bodies in the rubble and were now unsure how many had been inside.

"This is the biggest earthquake we've ever had here," he told.

"People are still frightened, especially after the aftershocks last night. Nobody dared to stay at home. Everyone slept on the roads or in car parks.

"The earthquake triggered many landslides. People could not get out of the area because of fallen trees and mounds of earth blocking roads."

The main hospital in the district was overwhelmed and tents had been set up in the building's car park to treat the flood of patients, he said.

He added supplies of food and water were in short supply but rescuers had succeeded in reaching the remote area.

Military, police and local government officials were trying to head to other affected areas on Wednesday by ground and in aircraft but some roads were blocked by landslips, the national disaster agency said.