LIMA, Peru (AP) _ A moderate earthquake rattled Lima on Friday, shaking buildings and causing office towers to sway, but there were no initial reports of damage, authorities said.

A preliminary estimate put the earthquake at magnitude 4.6, said Luis Vilcapoma, a spokesman for Peru's Geophysical Institute. A quake of that magnitude can cause moderate damage.

Most high-rise buildings were empty for Christmas Day. In Lima's sprawling shantytowns, where precarious hovels are vulnerable to earthquakes, people ran out into the streets fearing their houses would collapse.

They returned to their homes when there were no aftershocks, local radio station Radioprogramas reported.

A slide of rubble and rock caused by the quake temporarily blocked a stretch of Lima's Costa Verde highway, which runs along the beach.

Vilcapoma said the quake, at 9:26 a.m. local time (9:26 EST), hit seven miles southwest of downtown Lima in the district of Chorillos.

It was felt along Peru's central coastline, he said.