Three people were killed Tuesday when a 6.6-magnitude earthquake hit Indonesia's Sumatra island, officials said.

The quake struck deep underground shortly after midnight around 400 kilometres (250 miles) southeast of Banda Aceh on the northern tip of Sumatra, the US Geological Survey said.

Falling debris killed a 10-year-old boy as he slept in his home in Subulussalam, Aceh province, a doctor said.

"The boy was sleeping next to his mother when a wall collapsed and bricks fell onto his stomach, crushing him. His mother brought him to us but we couldn't save him in time," the doctor, named Hasbi, said.

Two other people were killed in separate incidents, the National Disaster Management Agency said.

Panicked residents rushed out of their homes, many crying and screaming for help, as the quake shook the area for around two minutes, according to an AFP correspondent.

"That was the strongest quake I'd ever felt. I thought the end of the world was here," 42-year-old farmer Abdul Kader Angkat said.

The jolt was also felt by residents in the cities of Banda Aceh and Medan, officials said.

The Hawaii-based Pacific Tsunami Warning Center said the quake was too far inland to generate a tsunami.

Indonesia sits on the Pacific "Ring of Fire", where the collision of continental plates causes high seismic activity.

Aceh was devastated when a 9.1-magnitude quake off Sumatra in December 2004 triggered a huge tsunami that killed more than 220,000 people around the Indian Ocean.