Southern Greece was hit by a magnitude-6.7 earthquake, the U.S. Geological Survey said.

The temblor hit today at 12:09 p.m. local time, and struck at a depth of 30 kilometers, about 230 kilometers (143 miles) southwest of Athens, the agency said.

The epicenter was under the sea, west of the Peloponnese peninsula in southern Greece, Gerassimos Houliaras, a seismologist at the Athens Observatory, said today in an interview on state Net television channel.

''We haven't heard reports of any damages yet,'' Houliaras said. He advised people to leave their homes in the Peloponnese and move to open places.

''The great depth of the quake averted damage on the surface,'' Efthymios Lekkas, another seismologist, said on Net.

Strong earthquakes are common in Greece because the country lies in one of the world's most active earthquake zones, between Europe and Africa. In September 1999, an earthquake measuring 5.9 hit Athens, resulting in the deaths of 143 people.

The U.S. Geological Survey reported that a second earthquake with a magnitude of 6.4 struck about two hours after the first tremor. ''It was in the same region,'' Athens Observatory seismologist George Stavrakakis said on Skai radio. No damage was reported from the second quake.

To contact the reporter on this story: John Deane in London at .