SUMATRA, Indonesia - An earthquake with a magnitude of 7.7 rattled the Indonesian island of Sumatra on Tuesday, shaking buildings and causing blackouts. There were no immediate reports of injuries.
The quake struck at 5:15 a.m. local time and was centered 125 miles northwest of Sibolga, in Sumatra, a major island in western Indonesia, the U.S. Geological Survey reported. It was about 28 miles deep, the agency said.
A tsunami watch was issued for the region, said the Pacific Tsunami Warning Center in Honolulu.
Several aftershocks struck after the initial temblor.
Japan's Kyodo news agency reported blackouts in Medan and Banda Aceh, the capital of Aceh Province.
A Reuters photographer on Simeulue island, west of Aceh, said residents panicked and electricity was cut off after the quake, while Metro TV reported that people rushed to higher ground in some areas.
Aceh's governor said there were no reports of casualties or damage in the province.
A receptionist at the JW Marriott Hotel in Medan, the capital of the province of North Sumatra, told NBC News he felt the quake quite strongly. Guests came down to the lobby to find out what happened but the hotel did not appear to be damaged.
Flex Lilisuheri, a local guide in Buki Lawang, North Sumatra, said the quake violently shook houses. He told NBC people ran into the streets and the electricity went off.
The region was hit by a devastating quake on Dec. 26, 2004, when a temblor of between 9.1 and 9.3 generated a tsunami that swamped countries bordering the Indian Ocean. About 230,000 people died.