The area was hit by at least two dozen aftershocks including one that measured 5.6 magnitude.

At least 20 people were killed and dozens injured Thursday in a strong earthquake that rocked Indonesia's remote Maluku islands, triggering landslides that buried at least one of the victims, the disaster agency said.

Terrified residents ran into the streets as buildings fell in around them when the 6.5-magnitude quake hit in the morning.

"At least 100 people were injured and more than 2,000 evacuated," said national disaster mitigation spokesman Agus Wibowo who gave the latest death toll in statement.

Among those killed was an infant, he said.

Earlier, local disaster agency officials said some victims had been killed by falling debris while one person was buried in a landslide.

Another victim died of a heart attack asthe tremor hit, while one woman died after falling off her motorbike while fleeing to higher ground, officials said.

Residents of Ambon, a city of about 400,000 people, were seen helping injured residents in blood-stained clothes, while images showed wrecked homes with collapsed walls and rubble strewn on the ground.

Some patients fled a local hospital as the quake hit, prompting officials to set up makeshift shelters outside the building, an official said.

"The impact was felt across Ambon city and surrounding areas," said Rahmat Triyono, head of the earthquake and tsunami division at Indonesia's Meteorology, Climatology and Geophysical Agency (BMKG).

"Many people were woken up by the shaking... it felt like a truck was passing by."

The US Geological Survey said the quake struck about 37 kilometres (23 miles) northeast of Ambon