A powerful earthquake that rocks Nias Island in Indonesia early Tuesday has destroyed at least 500 houses in the town of Gunung Sitoli, capital of Nias regency, but the estimated death toll cannot be made available immediately, an official said.

"According to reports from the military commander and the vice regent in Nias, the quake destroyed 80 percent of the town and flattened at least 500 houses," said TB Silalahi, a close aide to President Susilo Bambang Yudhoyono who has been sent to the island.

"We fear people were buried in their houses," he was quoted by the Antara news agency as saying.

He said death toll is estimated at "hundreds" but local officials cannot confirm any figure immediately.

The 8.7-magnitude quake also destroyed telecommunication and electricity networks, airport and roads.