YANGON, Myanmar -- Myanmar's military regime allowed in the first major international aid shipment yesterday, but it snubbed a U.S. offer to help victims of last weekend's cyclone.

Four airplanes carrying high-energy biscuits, medicine and other supplies reached Yangon, U.N. officials said. Two of four U.N. experts who flew in to assess the damage were turned back at the airport for unknown reasons, said John Holmes, the U.N. relief coordinator.

Five days after the storm, the junta continued to stall on visas for U.N. teams and other foreign aid workers eager to deliver food, water and medicine to survivors amid fears the death toll could hit 100,000.

Many potential donors fear that aid sent without any oversight from outside only will wind up in the hands of the army.

Among those stranded in Thailand were 10 members of the USAID Disaster Assistance Response Team. Air Force transport planes and helicopters packed with supplies also waited there.

"We are in a long line of nations who are ready, willing and able to help, but also, of course, in a long line of nations the Burmese don't trust," U.S. Ambassador Eric John told reporters in Thailand's capital, Bangkok.

Myanmar's isolationist regime issued an appeal for international assistance after winds of 120 mph and a storm surge up to 12 feet high pounded the Irrawaddy delta Saturday.

But the junta has been accused of dragging its feet despite emerging reports of entire villages submerged, bodies floating in salty water and children ripped from their parents' arms.

Myanmar's state media said Cyclone Nargis killed at least 22,997 people and left 42,019 missing, mostly in the Irrawaddy delta. Shari Villarosa, who heads the U.S. Embassy in Yangon, said the number of dead could eventually exceed 100,000 because of illnesses.

In the swampy delta, a stench rose from human and animal corpses. Someone had written on a black asphalt road in Kongyangon village: "We are all in trouble. Please come help us." A few feet away, the desperate plea, "We're hungry."

By rejecting the U.S. aid offer, the junta is refusing to take advantage of Washington's enormous ability to deliver aid quickly, which was evident during the 2004 Indian Ocean tsunami that killed 230,000 people in a dozen nations.

The first foreign military aid following that disaster reached the hardest-hit nation, Indonesia, two days later.

With the Irrawaddy delta's roads washed out and the infrastructure in a shambles, large swaths of the region are accessible only by air.

The U.S. government, which has strongly criticized the junta's suppression of pro-democracy activists, will have to convince the generals that Washington has no political agenda, Tim Costello, chief executive of World Vision Australia, said.

Gordon Johndroe, President Bush's national security spokesman, said the U.S. was working to gain permission to enter Myanmar.

One American official, Ky Luu, director of the U.S. office of foreign disaster assistance, created a stir by saying one option being considered was air-dropping aid without permission. But Defense Secretary Robert Gates quickly said he couldn't imagine that happening.