A 6.0 magnitude earthquake shook northern Italy before dawn Sunday, killing at least six people and destroying centuries-old buildings and churches across the region.

The U.S. Geological Survey says the quake was centered about 35 kilometers northwest of Bologna.

It struck about 4 a.m. local time, sending panic-stricken residents running into the streets. A series of aftershocks followed. The strongest was 5.1 magnitude.

Many of those residents say they are scared to go back into their homes, fearing more aftershocks.

The quake turned historic buildings and churches — some as old as 1,500 years — into piles of rubble and dust. The Italian culture ministry says the damage is significant.

Italian Prime Minister Mario Monti has sent his condolences to the victims. He plans to leave the NATO summit in Chicago early to return home.