Banda Aceh, Indonesia  A huge earthquake and strong aftershocks struck off Indonesia's Sumatra island yesterday, triggering an Indian Ocean-wide tsunami alert that sent terrified people fleeing from the coast.

The 8.6-magnitude quake hit 431 kilometres off the city of Banda Aceh at 0838 GMT, and was followed by another undersea quake measured at 8.2, the US Geological Survey said.

Panicky residents poured into the streets of Banda Aceh, which was near the epicentre of a 9.1-magnitude quake in 2004 that unleashed an Indian Ocean tsunami that killed 220,000 people.

Yesterday's quake was felt as far afield as Thailand, where skyscrapers in the capital Bangkok swayed. India, Indonesia, Kenya, Malaysia, Reunion Island, Sri Lanka, Thailand and Myanmar all issued alerts or evacuation orders which were later lifted.

Small tsunamis hit Indonesia and Thailand, with waves of up to 80 centimetres in Aceh, but there were no reports of damage or casualties. US seismologists then cancelled the tsunami warning, saying the quakes had generated only small waves and were nowhere near the scale of the disasters that struck Asia in 2004 and Japan last year.

There were chaotic scenes as people grabbed their families and raced through crowded streets, with motorbikes and cars jostling for space in many Asian cities.

In Sri Lanka the disaster management centre asked residents on the coast to move inland to avoid being hit by any large waves.

Thailand issued an evacuation order for its Andaman coast, a popular tourist destination.

India issued a red high-level tsunami warning for the Andaman and Nicobar Islands, located in the Indian Ocean, and lower alerts for several other eastern coastal states.

In Oman, Eisa Al Hussain, Director, Earthquake Monitoring Centre at the Sultan Qaboos University, told Gulf News that he saw no impact of tsunami threat although Oman was among the 28 countries put on alert earlier in the day.

— With inputs from Sunil K. Vaidya, Bureau Chief