PADANG, INDONESIA (AP) -- Officials say a second earthquake has hit Indonesia on the heels of Wednesday's temblor that trapped thousands of people under collapsed buildings and killed more than 500.

A government official says the toll is expected to get higher.

The U.S. Geological Survey says Thursday's temblor was a powerful, shallow inland earthquake with a preliminary magnitude of 6.8.

Shallow, inland earthquakes generally are more destructive. There were reports that the second quake badly damaged dozens of additional buildings.

The 7.6 magnitude undersea temblor Wednesday started fires, severed roads and cut off power and communications to Padang, a coastal city of 900,000 on Sumatra island. Thousands fled in panic, fearing a tsunami.

Officials say at least 500 buildings in Padang collapsed or were badly damaged.

Officials say the death toll from the tsunami that crashed over some South Pacific islands is at least 150.

Shortly after Samoa's prime minister told reporters 110 people had died in his country, the police commander said the toll would rise and it could take weeks to account for all the missing.

At least 31 people were killed on American Samoa and nine in Tonga by the tsunami Tuesday morning, which occurred after a magnitude 8.0 quake struck off Samoa.

Among the hardest hit regions was the southeast coast of Samoa. Several tourist resorts there were wiped out.

Military transports are ferrying medical personnel, food, water and medicine to Samoa and American Samoa.

A cargo plane from New Zealand brought in a temporary morgue and a body identification team.

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