Deadly northern Italy earthquake hits heritage sites

An earthquake in northern Italy has killed at least four people and caused serious damage to buildings in several towns, local officials say. 

The magnitude-six quake struck in the middle of the night, about 35km (22 miles) north of the city of Bologna.

The four victims were killed by falling masonry. Italian media report two more quake-related deaths.

The tremor caused "significant damage to the cultural heritage" of Emilia Romagna region, the government said.