In Indonesia's Banda Aceh city, an official ceremony at the Baiturrahman Grand Mosque kicked off a series of memorials across Asia with a three-minute-long siren at the exact time a major earthquake caused giant waves on December 26, 2004.

A 9.1-magnitude earthquake off Indonesia's western tip generated a series of massive waves that pummelled the coastline of more than a dozen countries from Indonesia to Somalia.

Beachside memorials and religious ceremonies will be held across the worst-hit countries to mark the anniversary.

Indonesia suffered the highest death toll, with more than 160,000 people killed along its western coast while thousands also died in Sri Lanka, India and Thailand.

In Sri Lanka, where more than 35,000 people perished, survivors and relatives were to gather to remember around 1,000 victims who died when waves derailed a passenger train.

In Thailand, where half of the more than 5,000 dead were foreign tourists, unofficial vigils were expected to accompany a government memorial ceremony.

Nearly 300 people were killed as far away as Somalia, as well as more than 100 in the Maldives and dozens in Malaysia and Myanmar, according to EM-DAT, a recognised global disaster database.