Some of the villages in the tsunami's path simply do not exist anymore
Indonesian rescue teams are battling to reach an estimated 400 people believed to be missing since a tsunami struck small islands off the coast of Sumatra.
Officials say a 3m-high wave crashed into the Mentawai islands after a quake on Monday, killing at least 154 people.
Rescuers are now in the region, facing bad weather and post-quake aftershocks in villages levelled by the wave.
Indonesia's president is cutting short a trip to Vietnam to visit the islands and oversee the relief operation.
Officials said Susilo Bambang Yudhoyono would fly back from a meeting with regional leaders to help deal with the tsunami aftermath.
He will also be briefed on the rescue effort on Java, where an erupting volcano has caused chaos.
US President Barack Obama, who spent some of his childhood in Indonesia, has spoken of his sadness at the deaths.
"At the same time, I am heartened and encouraged by the remarkable resiliency of the Indonesian people and the commitment of their government to rapidly assist the victims," he said in a statement.
He said the US was ready to help in any way.
Higher ground:
At least 10 villages are thought to have been flattened by the tsunami, which was caused by a 7.7-magnitude earthquake late on Monday.
Waves reached 3m (10ft) high and the water swept inland as far as 600m on South Pagai.
The first images emerging from the Mentawai Islands show empty clearings where homes and buildings once stood, levelled and cleared by the power of the wave.
n the tsunami zone, regional disaster official Hermansyah confirmed that the number killed had risen to 154, and said those who had survived 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.
Rough seas were making it difficult to ship aid to the Mentawai islands from Padang, the nearest major port on Sumatra. Forecasters say the bad weather is likely to continue in the coming days.
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 suggested 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."
Indonesia launched a purpose-built tsunami warning system two years ago which was aimed to be running completely by 2010. Monday's earthquake was one of its most serious tests, but it is unclear whether the western Sumatra area is covered by an operational system. Mr 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.
The Indonesian Red Cross said it was despatching a team to the islands, and would send 1,000 tents.
The country's vice-president is due to fly to the area with top military and health officials later.
He said that those displaced needed tents, blankets, food, drinking water and medicine.
The Indonesian Red Cross said it was despatching a team to the islands, and would send 1,000 tents.
The country's vice-president is due to fly to the area with top military and health officials later.
On Tuesday, local fisheries official Hardimansyah said most buildings in the South Pagai coastal village of Betu Monga had been destroyed.
"Of the 200 people living in that village, only 40 have been found - 160 are still missing, mostly women and children," Hardimansyah told Reuters news agency.
"We have people reporting to the security post here that they could not hold on to their children, that they were swept away. A lot of people are crying."
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.
"Of the 200 people living in that village, only 40 have been found - 160 are still missing, mostly women and children," Hardimansyah told Reuters news agency.
"We have people reporting to the security post here that they could not hold on to their children, that they were swept away. A lot of people are crying."
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.
Source: BBC
