Indonesian rescue teams are battling to reach an estimated 500 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 112 people. Rescuers are now in the region, facing bad weather and post-quake aftershocks as they search for survivors. 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 In the tsunami zone, regional disaster official Hermansyah said 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. 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. Vice-President Boediono 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," he 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 tsunami 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 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