JAKARTA - A 6.9-magnitude earthquake struck off Indonesia's western province of West Sumatra earlier Tuesday and was potential to trigger a tsunami, forcing thousands of residents to flee the coastal areas, the weather agency and officials said.

The earthquake happened at 03:00 am Jakarta time Tuesday (2000 GMT Monday), with the epicenter at 177 km northwest of Mentawai Islands district and a depth of 84 km under the seabed, said the country's meteorology, climatology and geophysics agency.

A tsunami warning has been put in place by the agency, which revised the quake magnitude to 6.9 from its initial report of 7.3.

Over 2,000 residents have fled the coastal areas, heading to higher grounds in the sub-districts of Siberut Barat (West Siberut) and Siberut Utara (North Siberut) of Mentawai Islands district, said Amir Ahmari, head of the emergency and logistics unit of the disaster management and mitigation agency in Mentawai district.

"The tremors were strongly felt in the Siberut Barat and Siberut Utara sub-districts. The residents there rushed to higher grounds," Ahmari told Xinhua by phone.

The official said that so far, he had not got initial reports of damages or casualties, but the assessment of the risks will be continuously carried out later.

Based on visual observation, so far there were no injuries, casualties and damages after the quake, according to Abdul Muhari, spokesman of the National Disaster Management and Mitigation Agency.

Head of the meteorology, climatology and geophysics agency Dwikorita Karnawati said that the surface of the water had risen by 11 centimeters, adding that the agency forecast the rise would be no more than 0.5 meters high.