The US Geological Survey said the quake had a preliminary magnitude of 7.6 and struck under the island of Simeulue off the western coast of Sumatra - the region worst hit in the 2004 Indian Ocean tsunami.

Rustam Pakaya, the head of the Indonesian Health Ministry's disaster center, said "many" buildings on Simeulue were damaged and three people were killed. He said at least 25 others were seriously injured.

The Pacific Tsunami Warning Center issued an alert saying coastlines close to the epicenter were at risk of a possible tsunami. It canceled the warning two hours later after no large waves were generated.

The quake was felt across much of western and northern Sumatra, where many people fled swaying homes and buildings.

In coastal areas, residents ran to high ground in fear of a tsunami.

"Everything shook very strongly for more than a minute and I ran along with the others. I heard people screaming in panic," said Ahmad Yushadi, a resident of Aceh province on the northern tip of the island.

Quakes measuring 7 and above can cause major damage in built-up areas.

Simeulue is home to around 75,000 people, but most people live in simple village homes that do not typically cause major injuries or death to inhabitants if they collapse.