MENTAWAI ISLANDS, Indonesia - Planes and helicopters packed with rescue workers and supplies landed for the first time Wednesday on remote Indonesian islands that were pounded by a 10-foot (three-meter) tsunami, sweeping away villages and killing at least 272 people.

The first aerial surveys of the region revealed huge swaths of land underwater and the crumbled rubble of homes torn apart by the wave. One lay tilted, resting on the edge of its red roof, with tires and slabs of concrete piled up on the surrounding sand.

Two days after a powerful earthquake triggered the wave, the casualty count was still rising as rescuers and disaster officials finally reached the Mentawai island chain, which was closest to the epicenter and the worst hit. Bad weather had kept them away.

On Wednesday evening, disaster official Ade Edward nearly doubled the estimated number of casualties to 272 dead with 412 missing.

President Susilo Bambang Yudhoyono, meanwhile, cut short a state visit to Vietnam to deal with two major disasters that struck Indonesia in less than 24 hours. The country's most volatile volcano, Mount Merapi, 800 miles (1,300 kilometers) to the east, erupted at dusk Tuesday, sending up searing ash clouds and killing more than two dozen people.

Both events fell along Indonesia's portion of the Pacific Ring of Fire, a series of fault lines that are prone to earthquakes and volcanic activity stretching from the Western Hemisphere through Japan and Southeast Asia.

Disaster officials were still trying to reach more than a dozen villages on the Mentawais - a popular surfer's destination that is usually reachable only by a 12-hour boat ride.

The 7.7-magnitude quake that struck late Monday just 13 miles (20 kilometers) beneath the ocean floor was followed by at least 14 aftershocks, the largest measuring 6.2.