JAKARTA, Indonesia — A powerful earthquake struck waters off eastern Indonesia early Monday, briefly generating tsunami warnings for coastlines within 600 miles (1,000 kilometers) of the epicenter.
Thousands of people in nearby coastal towns fled homes, hotels and hospitals in panic, but there were no immediate reports of serious damage or injuries.
The U.S. Geological Survey put the quake's magnitude at 7.5 and said it struck 54 miles (135 kilometers) from the nearest city, Gorantalo, located on Sulawesi island. It was centered 13 miles (21 kilometers) beneath the sea and was followed by two strong aftershocks.
The Pacific Tsunami Warning Center said the temblor had the potential to generate a destructive tsunami along coasts within 600 miles (1,000 kilometers).
But even after local officials lifted the tsunami alert, frightened Sulawesi residents were refusing to return to their homes.
Gusnar, the deputy governor of Gorantalo province, told el-Shinta radio he had been in touch with district chiefs and there were "no reports of serious injuries or significant damage." Like many Indonesians, he goes by only one name.
Robert Bano, a Gorantalo resident, said the massive quake shook homes for more than two minutes and sent many people fleeing their homes, some, like him, with crying children.
Some guests streaming from Paradiso Hotel were so afraid they fainted, the official news agency Antara reported.
A witness in the city of Poso said patients from at least one hospital were evacuated.
Indonesia is prone to seismic upheaval due to its location on the so-called Pacific "Ring of Fire," an arc of volcanos and fault lines encircling the Pacific Basin.
In December 2004, a massive earthquake off Indonesia's Sumatra island triggered a tsunami that battered much of the Indian Ocean coastline and killed more than 230,000 people — 131,000 of them in Indonesia's Aceh province alone.
A tsunami off Java island last year killed nearly 5,000.