A U.S. helicopter on a relief mission crashed in a rice paddy near the Banda Aceh (search) airport Monday, injuring two servicemen. Schools reopened in Indonesia and Sri Lanka for the first time since the Dec. 26 tsunami, but with so many children among the more than 150,000 victims, the scene was far from normal.

Workers, meanwhile, struggled to recover 50,000 bodies the Indonesian government said were "scattered" throughout the region.

The U.S. military said the Seahawk helicopter "executed a hard landing" and there was no evidence it was shot down 500 yards from the airport in Banda Aceh, capital of Indonesia's hard-hit Aceh province and the hub of international aid operations. Lt. Cmdr. John M. Daniels blamed the crash on a "possible mechanical failure."

He said one person fractured an ankle and the other dislocated his hip. The other eight suffered "no significant injuries," he said.

"There was no fireball but a little smoke. It landed on its side," said Capt. Joe Plenzler, adding that the helicopter's propeller was twisted from the impact. Fifteen Seahawk helicopters from the Lincoln group have been flying up to nine hours a day on aid missions. Normally they fly a maximum of three to four hours a day.

The crash came amid heightened security concerns in several tsunami-hit areas with ethnic rebellions — particularly Aceh, where rebels have waged a separatist war in the province for nearly three decades. United Nations staff in Aceh are on high alert, and armed guards patrol their compounds amid fears of rebel attacks.

In Washington, President Bush said the United States "is committed today and we will be committed tomorrow" to tsunami victims, but he did not commit to any specific increase in the U.S. aid pledge of $350 million.

"We'll see," Bush said after receiving a report on the destruction from Secretary of State Colin Powell, just back from the area. "The dollars are demand driven."

Nations around the world have pledged more than $4 billion.

U.S. Marines came ashore at the devastated Indonesian fishing town of Meulaboh (search), riding a high-tech hovercraft that carried tons of food, water and a forklift. Only about 10 Marines landed, due to concerns by the Indonesian government about security and that the troops would be too much for the local infrastructure to handle.

"We're hoping that they will see that this went well, and ask us to come again," said Capt. Michelle Howard, commander of the Navy strike force that brought the Marines.

Nearly 2,000 Marines are now afloat off the Meulaboh coastline in two amphibious assault ships diverted from duty in Iraq. The ships carry two dozen helicopters, heavy equipment such as bulldozers and forklifts, and tons of food.

About 100 Marines and Navy troops splashed ashore in southern Sri Lanka for the first time, bringing heavy machinery to clear devastated areas. A huge landing craft ferried the heavy equipment — which included a bulldozer, trucks and a tram to clear heavy debris and rubble — from the USS Duluth to the beachfront in Koggala town, 12 miles east of the southern city of Galle.

Aftershocks from the massive Indian Ocean earthquake that spawned the killer waves, claiming more than 150,000 lives, continued to rattle survivors in the hardest-hit countries. A 6.2-magnitude temblor sent people scrambling from their homes early Monday in Banda Aceh. No injuries or damage were reported.

UNICEF confirmed two cases of measles in Indonesia, raising fears that the highly contagious and potentially deadly viral infection could take hold on devastated Sumatra island.

The U.N. children's agency is trying to vaccinate 600,000 people against the disease, which can be deadly to children if not treated, said UNICEF Indonesia spokesman John Budd. The mass vaccination drive in the Sumatra region began last week and is expected to take three weeks to complete.

Indonesian authorities promised to speed up the grim task of recovering and burying the dead. Welfare Minister Alwi Shihab said 58,281 bodies had been buried in the shattered area on the northern tip of Sumatra island. He said about 50,000 more are "scattered" around the region.

Some corpses remain trapped in collapsed buildings and rotting under debris in canals and rivers. Their stench still hangs over some areas of the provincial capital.

In Phang Nga, Thailand, a team of veterinarians armed with tranquilizer guns has been hunting stray dogs that are feeding on corpses. More than 70 have been seized, including 40 around the Yan Yao Buddhist temple, which was pressed into duty as an ad hoc mortuary in the province, where more than 4,000 people were killed by the tsunami.

Dr. Kiartichai Nirandorn of the Foundation for Stray Dogs said the animals will not be harmed or killed. Instead, they will be moved to a special kennel in western Thailand.

In the latest sign life is slowly returning to normal, children returned to school in Indonesia and Sri Lanka for the start of the new term — long before many institutions damaged in the disaster can provide proper education. Social workers hope the resumption of studies will help children overcome the trauma of the catastrophe.

About 80 students, some accompanied by their parents, showed up at the state-run Vidyaloka school for boys, in Galle, Sri Lanka — a tiny fraction of the 2,400 who are registered. Some had no uniforms.

In Indonesia, the government said Monday that 420 schools had been destroyed and 1,000 teachers killed in Aceh province, which was near the epicenter of the huge undersea quake that triggered the tsunami.

"The government will try to provide new teachers to Aceh and immediately to construct schools," Welfare Minister Alwi Shihab told reporters. "Meanwhile, tents can be used as school buildings as well as other public sites, like mosques."

In a rare happy story, a 22-year-old Indonesian, Ari Afrizal, was rescued at sea sometime late last week by the United Arab Emirates-registered AL Yamamah, said Sasheila Paramsothy, a spokeswoman for the shipping harbor Westport Malaysia.

Ari was swept out to sea when the tsunami hit his home in Aceh, Paramsothy said, adding that the ship crew has not provided other details.

U.N. Secretary-General Kofi Annan (search) was assessing damage in the Maldives, a low-lying string of coral atolls in the Indian Ocean that lost 82 people. The United Nations is now coordinating humanitarian relief efforts in all the countries affected by the disaster and is taking that responsibility "very, very seriously," Annan said.

A senior Navy officer involved in the humanitarian aid mission said the U.S. military is likely to remain in tsunami-devastated areas for an extended period.

"I don't see an end to this for a long, long time," Capt. Larry Burt said of the American presence on Sumatra island.

Burt is the commander of the air wing aboard the aircraft carrier USS Abraham Lincoln.

For more than a week, U.S. military helicopters have been rushing food, water and medical supplies to areas inaccessible to other aid workers and in desperate need.

Indonesian military chief Endriartono Sutarto told The Associated Press his forces were not conducting offensive operations against Acehnese rebels despite reports they attacked aid convoys and even briefly kidnapped Indonesian relief workers.

Sutarto said the workers were rescued by Indonesian forces but gave no further details.

Indonesia's military warned aid workers Sunday that rebels in Aceh were taking shelter in camps for survivors, but the government dismissed those claims Monday. The government also said rebels were not responsible for a shooting near the main U.N. compound on Sunday, contradicting earlier assertions by the country's military and police.

Welfare Minister Alwi Shihab said a troubled Indonesian soldier, not a rebel gunman, was responsible for the burst of gunfire. The soldier was in custody, Shihab said.