(Adds resident quotes, changes dateline)

BANDA ACEH, Indonesia, Dec 1 (Reuters) - A strong earthquake measuring 6.3 on the Richter scale struck off Indonesia's Aceh province on Saturday, although there were no immediate reports of damage or casualties, officials and residents said.

The quake's epicentre was 33 km (20 miles) southwest of Singkilbaru at a depth of 18 km (11 miles) and did not trigger a tsunami warning, the meteorology agency said by telephone text message.

The quake was felt in Nias island and other parts of Aceh, and also as far as West Sumatra, an official at the agency said later by telephone.

An official at the meteorology office in Aceh's capital, Banda Aceh, said no damage or injuries had been reported from areas closest to the epicentre.

Tarmizi, a resident in Aceh Singkil off Aceh's western coast, said the quake was felt strongly and people ran out of their homes in panic. "Thank God there have been no casualties here," he told Reuters by telephone.

Indonesia is located in a very active seismic region where several tectonic plates meet and is subjected to frequent tremors.

In December 2004, a powerful quake off Aceh triggered a huge tsunami in the Indian Ocean, killing around 230,000 people in neighbouring countries with most of the deaths in Aceh.

(Additional reporting by Harry Suhartono and Telly Nathalia in Jakarta

(Writing by Ed Davies and Ahmad Pathoni; Editing by Jeremy Laurence)

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