A 6.6-magnitude earthquake (search) struck in waters in the western part of the Pacific island group of Micronesia, the Hong Kong Observatory (search) said Monday. No casualties were immediately reported.

The temblor was centered about 200 miles northeast of the island of Yap, part of the Federated States of Micronesia, the observatory said in a statement. It was recorded in Hong Kong at 4:24 a.m., the statement said.