BANDA ACEH - A massive earthquake off Indonesia measuring 8.7 on the Richter scale triggered tsunami alerts around the Indian Ocean, causing panic three months after giant waves killed hundreds of thousands in the region.

There were no immediate reports of casualties from the undersea quake which was felt in neighbouring countries and prompted India, Malaysia, Sri Lanka and Thailand to join Indonesia in issuing alerts.

The quake hit a location between the island's main cities of Pedang and Medan in the Indian Ocean at around 11:09pm (Indonesian time) and lasted up to three minutes, said Ramlan of Indonesia's Meteorological and Geophysics Office.

In the United States the US Geological Survey measured the earthquake initially at 8.2 on the Richter scale, but later upgraded it to 8.7.

Sumatra bore the brunt of the December 26 magnitude-9.0 earthquake that triggered a tsunami which killed more than 273,000 people on shorelines around the Indian Ocean.

Thousands of people fled their homes in panic in Banda Aceh, the city at the northwestern tip of Sumatra after the three-minute quake struck at around 11:15pm (1615 GMT), according to an AFP reporter in the city.

Many headed for higher ground, while police called for calm and mosques broadcast messages saying: "Don't panic, there is no tsunami".

The earthquake was felt in Malaysia at 12.09am, sending residents of hotels and high rise buildings fleeing in Kuala Lumpur.

"I was sleeping and felt the bed shaking just after midnight," one woman who lives on the sixth floor of a downtown apartment block told AFP .

"Everybody rushed down out of our building and many others. People were just standing around in the streets."

A resident of Penang island off the northwest coast said the tremor disconnected phone lines, the Bernama news agency reported.

Tsunami alert

Tremors were also felt in Padang, the capital of neighbouring Sumatra province, where it downed powerlines, according to local Metro TV. No telephone contact was immediately possible with Padang or another major city, Medan.

Officials in India, Sri Lanka and Thailand took no chances, issuing warnings and urging citizens living along shorelines to evacuate their homes.

"We have just received an alert ... and have asked the fishermen down the coast to move towards the interior," said CV Shanker, a tsunami relief officer in India's southeastern Tamil Nadu state.

Thai meteorological department deputy director Lalith Chandrapala told AFP there was no report of any tsunami. "But we are asking people living along the coast to leave as a precaution."

"The earthquake is strong enough to issue the warning for people to evacuate as a prevention, particularly in the area affected by the tsunami last time," Thailand's deputy chief meteorologist Chalermchai Akekantrong told local TV.

People at the famous Patong beach on the tourist island of Phuket were already headed toward higher ground, TV reports said.

Similar scenes were reported in coastal cities and towns across Sumatra.

"I'm trying to find my family, there are all women, they were very scared and ran out of the house," said one man in Peurada village, in Sumatra's western Aceh province, who was searching for his relatives on a motorcycle.

"I have put everything I own on the roof," he added.

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