ATHENS, Greece -- A strong earthquake centred northwest of Athens shook Greece on Friday, causing frightened residents to run into the capital's streets and damaging several buildings. Authorities said four people were hospitalized with injuries, none of them serious.

The Athens Institute of Geodynamics gave the earthquake that struck at 2:13 p.m. local time (1113 GMT) a preliminary magnitude of 5.1. The U.S. Geological Survey reported a magnitude of 5.3.

Firefighters checked for people trapped in elevators amid power outages after the brief but jolting quake.

In central Athens, the Acropolis Museum was evacuated and closed for the rest of the day as a precaution, but the city's ancient monuments remained open.

Police patrols and helicopters were deployed to inspect areas close to the earthquake's epicenter near the town of Magoula. The patrols were scheduled to continue overnight as many local residents were expected to sleep outdoors waiting for aftershocks to subside.

Greek government spokesman Stelios Petsas said an abandoned building collapsed in western Athens and several other abandoned buildings elsewhere in the city had serious damage.

"I urge members of the public to remains calm. In Greece, we are well-acquainted with earthquakes," he said.

The most powerful quake to hit the Greek capital in the last 20 years came in 1999, when a temblor of magnitude 6.0 caused extensive damage and killed more than 140 people.

After Friday's quake, fire brigades reported receiving dozens of calls about people trapped in elevators. The shaking was caught on live cameras in the studios of state broadcaster ERT.

Gerasimos Papadopoulos, the senior seismologist at the Geodynamics Institute, said it was felt across southern Greece.

"It had a very shallow depth and that's why it was felt so strongly," he said, adding that the earthquake had been followed by a normal pattern of aftershocks.