The death toll from a tsunami that hit several remote islands in Indonesia has risen to at least 282, officials say.
Rescue teams on the Mentawai islands say hundreds are still missing, two days after a 7.7-magnitude earthquake triggered a tsunami in western Sumatra.
Officials say there were faults with an early warning system designed to alert locals to the 3m-high (10ft) wave.
Indonesia’s president has cut short a trip to Vietnam to visit the islands and oversee the relief operation.
Susilo Bambang Yudhoyono flew back from a meeting with regional leaders to help deal with the tsunami aftermath.
On Thursday he is expected to tour the region to monitor relief efforts. He will also be briefed on the rescue effort on Java, where an erupting volcano has caused chaos.
At least 10 villages on a series of islands known as the Pagai islands are thought to have been flattened by the tsunami, caused by the earthquake late on Monday.
Waves reached 3m high and the water swept as far as 600m inland on South Pagai.
The devastation is only now beginning to emerge, says BBC Indonesia correspondent Karishma Vaswani.
The first aerial images emerging from the Mentawai Islands showed bodies being collected from empty clearings where homes and buildings once stood before they were levelled by the power of the wave.
Corpses were strewn along beaches and roads, said district chief Edison Salelo Baja.
Rescue teams are now finally on the ground, but they have yet to reach the worst affected areas, with bad weather delaying their work, adds our correspondent.
Rough seas have made it difficult to ship aid to the Mentawai islands from Padang, the nearest major port on Indonesia’s largest island, Sumatra. Forecasters say the bad weather is likely to continue in the coming days.
The Indonesian military has also been mobilised, with helicopters bringing much-needed medical supplies and aid for affected villagers. The priority for rescue workers is to find as many survivors as they can, and get them to safe shelters.
Even as the rescue effort escalated, doubts emerged about the effectiveness of an expensive early-warning system designed after the lethal Indian Ocean tsunami of 2004.
Buoys that form part of a system monitoring ocean waves and measuring tides were out of action when the quake hit – possibly vandalised, officials told BBC Indonesian.
However, even a functioning warning system may have been too late for people in the Pagai islands.
“Pagai Islands is very close to the epicentre, so the waves reached Pagai Island in just five or 10 minutes. Even if the buoy is on, it is still too late to warn people,” said Ridwan Jamaluddin, of the Indonesian Agency for the Assessment and Application of Technology.
In the tsunami zone, regional disaster official Hermansyah said survivors were in urgent need of help.
“They have lost their houses and now need a lot of aid and assistance. There are some tents already arrived here but we still need many more,” he told AFP news agency.
The islands are described as extremely remote, with few roads or functioning telephone lines even before the tsunami hit, making it difficult to make an accurate assessment of the scale of the damage.
One man, a farmer named Borinte from the island of North Pagai, told AFP he had lost his wife and children. He confirmed that people living in the path of the tsunami received little or no warning.
“About 10 minutes after the quake we heard a loud, thunderous sound. We went outside and saw the wave coming. We tried to run away to higher ground but the wave was much quicker than us,” Borinte said.
“I’m so sorry that I couldn’t save my wife and children as I panicked and didn’t know what to do. I was swept away as well but I managed to survive by holding onto a wooden plank.”
Hermansyah told BBC Indonesian that about 4,000 households had been displaced by the tsunami, and that many people had fled to higher ground.
He said that those displaced needed tents, blankets, food, drinking water and medicine.
On Tuesday, local fisheries official Hardimansyah said most buildings in the South Pagai coastal village of Betu Monga had been destroyed and many women and children were missing.
The Indonesian Red Cross said it was despatching a team to the islands, and would send 1,000 tents.
US President Barack Obama, who spent some of his childhood in Indonesia, has spoken of his sadness at the deaths and offered US help if required.
The vast Indonesian archipelago sits on the Pacific Ring of Fire, one of the world’s most active areas for earthquakes and volcanoes.
More than 1,000 people were killed by an earthquake off Sumatra in September 2009.
In December 2004, a 9.1-magnitude quake off the coast of Aceh triggered a tsunami in the Indian Ocean that killed a quarter of a million people in 13 countries including Indonesia, Sri Lanka, India and Thailand.