Two strong earthquakes hit southern Greece on Thursday — one of them felt as far away as Italy and Egypt. No injuries were reported.

The first quake, with a preliminary magnitude of 6.5, hit just after noon the Athens Geodynamic Institute said. It was felt in Cairo and in the southern Italian regions of Puglia and Calabria.

The second struck about two hours later and had a slightly lower preliminary magnitude of 6.4. Both had epicenters beneath the seabed 140 miles south-southwest of Athens, the institute said.

The initial quake "was incredibly strong and lasted a long time," said Theodoros Salantis, mayor of Koroni, a seaside town near Kalamata, the closest city to the epicenter.

Schools were evacuated and people fled from their homes and offices in towns of southern Greece, but nobody was hurt. Authorities said there were reports of only minor damage such as cracks in walls and plaster falling off building exteriors, including at some schools.

The second quake was likely "a very strong aftershock of the first," said Gerasimos Papadopoulos, head of research at the Geodynamic Institute.

"We believe there will be more strong aftershocks," he said, adding that they could reach the level of magnitude 5.5 or 6. However, Papadopoulos said that inhabited areas near the epicenter were not believed to be in danger. "They are at a safe distance from the seismic activity. That is the important thing."

Greek television stations broadcast warnings by seismologists urging people in areas near the epicenter to stay away from buildings and remain outdoors.

Seismologist Efthymios Lekkas said the first quake struck at a depth of about 18 miles beneath the seabed, which helped prevent it causing serious damage. He added that initial indications were that it was the main earthquake, rather than a preliminary temblor.

Earthquakes are common in Greece, which is riddled with fault lines. In January, a 6.5 quake struck another part of southern Greece. Its epicenter was located deep underground and while it was felt across much of the country, it did not cause any injuries or serious damage.

In 1999, a 5.9-magnitude quake near Athens killed 143 people and left thousands more homeless.