HONG KONG -- A moderate earthquake struck under the sea near the island of Guam in the Pacific Ocean, Hong Kong seismologists said Monday. It was not immediately clear whether there were casualties or damage.

The magnitude-5.7 quake was recorded at 0108 GMT Monday, the Hong Kong Observatory said in a brief statement. The epicenter was about 90 kilometers (60 miles) south of the city of Agana, Guam, it said.

The small island of Guam is a US territory about 2,500 kilometers (1,550 miles) east of the Philippine capital, Manila.