Indonesia ? A moderate earthquake killed at least four people and damaged scores of buildings early today on Indonesia’s Sumatra island, which is still recovering from the 2004 Indian Ocean tsunami, witnesses and seismologists said.

The 5.5-magnitude tremor was felt across the western and northern parts of the island, sending people running from their homes and hotels, witnesses told the local el-Shinta radio station.

The quake struck just before dawn and was centered about 670 miles northwest of the capital of Jakarta, the U.S. Geological Survey said on its Web site. It was followed by a series of aftershocks.

At least four people were killed in one village in Mandailing Natal district when two houses collapsed, a witness told el-Shinta. Scores of other buildings were also damaged, he said.

About 30 minutes before the quake, a 5.8-magnitude tremor struck off Sumatra’s coast, the USGS said. No tsunami warning was issued as a result of that quake.