Survivors of the Indian Ocean tsunami have been paying tribute to the victims in Asian countries, as Thursday marks 20 years since the massive quake-triggered disaster.

The earthquake struck off the coast of the Indonesian island of Sumatra, generating a tsunami that reached a vast area spanning from Southeast Asia to East Africa. The disaster left more than 220,000 people dead or missing, and caused widespread damage.

Indonesia's Aceh province saw the largest number of casualties, with more than 160,000 people dead or missing. Residents and family members of the victims gathered for a commemorative ceremony.

A woman who was injured in the disaster when she was seven years old and lost her family expressed her gratitude for the assistance from the international community. She said the disaster claimed many lives but many people offered help as well.

In Sri Lanka, people held a ceremony in Hikkaduwa in the country's south. More than 1,200 people died when the tsunami engulfed a train.

A 64-year-old man whose sister and niece went missing said his heart is still filled with sadness and suffering. He stressed the need for preventive measures against tsunami.

An event was also held in southern Thailand. Many foreign tourists, including Japanese nationals, were among the victims. Foreign volunteers who worked in the aftermath of the disaster attended the memorial.

Passing on memories of the tsunami has become an urgent task, as awareness of disaster prevention appears to be receding in the affected areas.