JAKARTA, Indonesia — A powerful earthquake rocked Indonesia's northernmost province of Aceh Sunday and radio reports said several small buildings had collapsed and large waves had slammed the area's north coast.

Witnesses told Jakarta's el-Shinta radio station that nine people were killed in the quake, but there was no immediate way to confirm the casualty and damage reports.

There were conflicting reports on the size of the temblor, which struck about 8 a.m. and was centered about 100 miles off the west coast of Sumatra. The U.S. Geological Survey's Web site recorded a magnitude of 8.1, capable of massive damage. But Indonesian seismologists said the quake had a magnitude of 6.4. There was no way to immediately clarify the discrepancy.

In the provincial capital, Banda Aceh, 1,000 miles northwest of Jakarta, dozens of shops and small buildings collapsed, witnesses told el-Shinta.

"The ground was shaking for a long time," resident Yayan Zamzani told the station. "It must be the strongest earthquake in the last 15 years."

Residents in Banda Aceh as well as Lhokseumawe, a city about 125 miles southeast, told the radio station that large waves had hit coastal regions. In Lhokseumawe several houses had been damaged.

Telephone lines appeared to be out following the 8 a.m. quake with no calls going through.

Indonesia, a country of 17,000 islands, is prone to seismic upheaval because of its location on the margins of tectonic plates that make up the so-called the "Ring of Fire" around the Pacific Ocean basin.

The quake was felt as far away as the Thai capital, Bangkok, and came just three days after an 8.1 quake struck the ocean floor between Australia and Antarctica, causing buildings to shake hundreds of miles away but no serious damage or injury.

Quakes reaching a magnitude 8 are very rare. A quake registering magnitude 8 rocked Japan's northern island of Hokkaido on Sept. 25, 2003, injuring nearly 600 people. An 8.4 magnitude tremor that stuck off the coast of Peru on June 23, 2001, killed 74.