At least 97 people were killed and scores injured when a strong earthquake struck western Indonesia Wednesday and flattened hundreds of homes and mosques, with officials warning the death toll would likely rise.

"So far 97 people have been killed and the number keeps growing," Aceh military chief Tatang Sulaiman told AFP.

The shallow 6.5-magnitude quake struck Pidie Jaya district in Aceh province at dawn as many in the mainly Muslim region on Sumatra island were preparing for morning prayers.

The death toll has continued to rise as rescue crews sift through the devastation, sometimes by hand, to find those trapped beneath the rubble.

National disaster agency spokesman Sutopo Purwo Nugroho said 52 people were confirmed dead so far with around 270 others injured, dozens of them seriously.

“Those figures are expected to rise given the massive destruction,” he told reporters.

An AFP correspondent said dazed residents were wandering debris-strewn streets, unable to return to their damaged homes in fear of aftershocks.

In the hard-hit town of Meureudu, terrified residents rushed outside as their homes buckled and crumbled under the force of the quake.

Mosques toppled into ruins, their spire-topped minarets smashing to the ground, while shopfronts collapsed and took down the homes above them.

Hasbi Jaya, 37, watched in horror as his two children were trapped beneath the wreckage of their family home.

He pulled them unconscious from the rubble and staggered through the dark towards the district hospital. “Everything was destroyed,” Jaya told AFP.

“It was pitch black because the electricity was out. I looked around and all my neighbours' homes were completely flattened.”

Hospital overwhelmed

The sole hospital in Pidie Jaya was quickly overwhelmed, with patients being treated on the grass out front or sent to neighbouring districts with better facilities.

The district health office chief Said Abdullah said nearly 200 injured had arrived since the quake, but many would not enter the hospital for fear of aftershocks.

“We are treating people outside. We took the beds out because nobody is daring enter the hospital,” he told AFP.

The local disaster agency is struggling to provide relief to those made homeless, with shops closed or levelled in the quake.

“People cannot buy their basic needs such as food and water,” local agency head Puteh Manaf told AFP, adding temporary kitchens had been erected in the worst-hit areas.

A hospital and school had sustained heavy damaged, while 10,000 students at Islamic boarding schools across the province had been affected by the quake, Nugroho said.

Many residents, jolted by the force of the quake, fled to higher ground for fear of a tsunami but no alert was issued.

A huge undersea earthquake in 2004 triggered a tsunami that engulfed parts of Aceh and other countries around the Indian Ocean, killing more than 170,000 people in Indonesia alone.

Indonesian seismologists said the latest earthquake was felt across much of Aceh province, with many aftershocks following the initial tremor.

The US Geological Survey upgraded the magnitude to 6.5 from an initial reading of 6.4 and issued a yellow alert for expected fatalities and damage.

Indonesia experiences frequent seismic and volcanic activity due to its position on the Pacific “Ring of Fire”, where tectonic plates collide.

Aceh lies on the northern tip of Sumatra island, which is particularly prone to quakes.

In June a 6.5-magnitude quake struck off the west of Sumatra, damaging scores of buildings and injuring eight people.