A strong earthquake measuring 6.6 magnitude struck central Italy on Sunday, causing the collapse of more buildings and historic churches in small cities and towns already shaken by tremors in the past week.

The quake measured 7.1 according to an initial estimate by the US Geological Survey and was later revised to 6.6, the biggest since almost 300 people were killed in central Italy on Aug 24 by a quake that levelled several small towns.

While there were no immediate reports of casualties on Sunday, damage was substantial.

Live television coverage showed the collapse of a church in the centre of Norcia, a town near Perugia in Umbria. Parts of the town had already been sealed off.

Buildings damaged in Norcia included the historic Basilica of St. Benedict and the town hall.

Sunday's earthquake followed a series of tremors to strike the country in the past five days.

It was felt as far north as Bolzano, near the border with Austria and as far south as the Puglia region at the southern tip of the Italian peninsula and was felt strongly in the capital Rome.

A series of strong earthquakes struck the area on Wednesday.

(Feature image source: Twitter/CBS News)