SYDNEY, Australia — An earthquake struck today under the Pacific Ocean floor near Samoa, generating a tsunami that could have been destructive if it had been closer to land, authorities said. No damage was immediately reported.

U.S. Geological Survey reported the quake as having a magnitude of 6.7 and striking 27 miles beneath the sea floor about 185 miles southwest of Pago Pago, American Samoa, at about 7:20 p.m. local time.

The Hawai'i-based Pacific Tsunami Warning Center reported the quake as magnitude 7 and recorded a 3-inch rise in sea levels near the epicenter.

Sefo Fuiono, a police constable in the capital of Samoa, Apia, said buildings swayed and shook for about five minutes during the quake, but there was no damage or injuries reported, and no panic among residents.