A strong earthquake rattled the southern Philippine island of Mindanao early Saturday, but there were no reports of any injuries or damage and no tsunami warnings were issued.

The quake, which hit at 2:17 a.m., had a magnitude of 6.4, according to the U.S. Geological Survey. The Philippine Institute of Volcanology and Seismology measured the magnitude at 6.5.

The institute said the quake's epicenter was 22 kilometers (13 miles) northeast of southern Tandag city, and 832 kilometers (517 miles) southeast of Manila, the capital. It hit at a depth of 78 kilometers (48 miles).

"There was no damage, no casualties," Civil Defense chief Benito Ramos said hours after the temblor hit. "The earthquake was strong, but its source was deep and far."

The institute recorded several aftershocks, but Ramos said they were hardly felt in the area. He said no tsunami warnings were issued.

Surigao del Sur provincial administrator Efren Rivas said about 1,000 Tandag residents fled to the elevated grounds of the provincial capitol when the quake struck but returned to their homes shortly after.

The Philippine archipelago is located in the Pacific "Ring of Fire," where earthquakes and volcanic activity are common. A magnitude-7.7 quake killed nearly 2,000 people on the northern island of Luzon in 1990.