Rescuers battled through landslides and blocked roads Wednesday to reach survivors from an earthquake in Indonesia's Aceh province that has killed at least 22 people, including several children who died when a mosque collapsed.

More than 200 people were also injured in Aceh's remote, mountainous interior when the strong 6.1-magnitude quake struck the north of Sumatra island 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.

Rescuers dug all night with an excavator through the rubble of the mosque looking for more children believed to be trapped but no more bodies had as yet been found, an AFP reporter at the scene said.

Most houses in the village had collapsed and residents were digging through the remains of the buildings with their bare hands to search for their belongings, the reporter said.

Bodies of the dead were laid out and covered in blankets at a makeshift emergency health post in the village.

"This is the biggest earthquake we've ever had here," Subhan Sahara, head of the district's disaster agency, told AFP.

"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 outside to treat the flood of patients, he said, adding that food and water were in short supply.

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

The agency dispatched a helicopter from neighbouring Riau province to assist in rescue efforts, while an air force plane was also deployed to assess the damage.

"So far 22 people died, 210 people were injured, and thousands of buildings and homes were damaged in the quake," disaster agency spokesman Sutopo Purwo Nugroho said.

The casualties were spread over the two worst-hit districts of Central Aceh and Bener Meriah, he said. Scores of people were being treated at hospitals across the region.

In Bener Meriah, about 300 people camped out overnight in open spaces, such as football fields, as the area was hit by strong aftershocks, Fauzi, an official from the local disaster agency, told AFP.

He said many were in desperate need of food.

"There were strong aftershocks last night and people didn't want to go back home, so they stayed in the open overnight, but we don't have enough tents," said the official, who like many Indonesians goes by one name.

"We have a power outage now and communications are unreliable," he added.

People ran outside in the provincial capital Banda Aceh as the quake -- some 320 kilometres (200 miles) away -- shook houses, and in Medan city to the south of the province.

Aceh, on the northern tip of Sumatra, is regularly hit by quakes. The huge quake-triggered tsunami of 2004 not only killed tens of thousands in the province, but also many in countries around the Indian Ocean.

In April last year an 8.6-magnitude quake struck 431 kilometres off Banda Aceh, prompting an Indian Ocean-wide tsunami alert.

Five people died and seven were injured in Aceh in the quake and following aftershocks.

In September 2009 a major earthquake near Padang city on Sumatra killed more than 1,000 people.

Indonesia sits on the Pacific "Ring of Fire" where tectonic plates collide, causing frequent seismic and volcanic activity.