'I thought it was doomsday': Asia mourns tsunami dead 20 years on

Tearful mourners have gathered in prayer as ceremonies began across Asia to commemorate the more than 220,000 people who lost their lives two decades ago when a tsunami struck coastlines around the Indian Ocean, one of the world's worst natural disasters.

In Indonesia's Aceh Province where more than 100,000 people were killed, a siren rang out at the Baiturrahman Grand Mosque to kick off a series of memorials around the region including in Sri Lanka, India and Thailand, which the tsunami hit hours later.

"I thought it was doomsday," said Hasnawati, a 54-year-old teacher who goes by one name, at the Indonesian mosque which was damaged by the tsunami.

"On a Sunday morning where our family were all laughing together, suddenly a disaster struck and everything's gone. I can't describe it with words."

Some mourners sat and cried at Aceh's Ulee Lheue mass grave, where around 14,000 are buried, while some villages held their own prayers around the province as they remembered the tragedy that devastated entire communities.

Indonesians will later visit a larger mass grave and hold a communal prayer in the provincial capital Banda Aceh, while beachside memorials and religious ceremonies were starting in Sri Lanka, India and Thailand, some of the worst-hit countries.

Victims of waves as high as 30 metres (98 feet) included many foreign tourists celebrating Christmas on the region's sun-kissed beaches, bringing the tragedy into homes around the globe.

The seabed being ripped open pushed waves at double the speed of a bullet train, crossing the Indian Ocean within hours.

In Thailand, where half of the more than 5,000 dead were foreign tourists, commemorations began early in Ban Nam Khem, the country's worst-hit village.

Tearful relatives of the dead laid flowers and wreaths at a curved wall in the shape of a tsunami wave with plaques bearing victims' names.

Napaporn Pakawan, 55, lost her older sister and a niece in the tragedy.

"I feel dismay. I come here every year," she said in the village.

"Times flies but time is slow in our mind."

Unofficial beachside vigils were also expected to accompany a Thai government memorial ceremony.

Candlelight, train vigils

A total of 226,408 people died as a result of the tsunami, according to EM-DAT, a recognised global disaster database.

There was no warning of the impending tsunami, giving little time for evacuation, despite the hours-long gaps between the waves striking different continents.

But today a sophisticated network of monitoring stations has cut down warning times.

Indonesia suffered the highest death toll, with more than 160,000 people killed along its western coast.

"It feels like it just happened yesterday. Whenever I am reminded of it, it feels like all the blood rushes out of my body," said Nilawati, a 60-year-old Indonesian housewife who lost her son and mother.

The disaster also ended a decades-long separatist conflict in Aceh, with a peace deal between rebels and Jakarta struck less than a year later.

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

The mourners will board the restored Ocean Queen Express and head to Peraliya - the exact spot where it was ripped from the tracks, around 90 kilometres (56 miles) south of Colombo.

A brief religious ceremony will be held with relatives of the dead there while Buddhist, Hindu, Christian and Muslim ceremonies are also organised to commemorate victims across the South Asian island nation.

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.

"My children, wife, father, mother, all of my siblings were swept away," said Indonesian survivor and fisherman Baharuddin Zainun, 70.

"The same tragedy was felt by others as well. We feel the same feelings."