A strong earthquake struck northern Italy on Tuesday, killing at least six people and spreading panic among residents still living in tents after a tremor shook the region just over a week ago, destroying their homes.

Italian news agencies said six people were confirmed dead and many people were injured.

"The situation is very serious, some people are stuck under the rubble," Alberto Silvestri, the mayor of the San Felice sul Panaro told television channel SkyTG24.

The 5.8-magnitude quake struck near Modena and was felt across much of northern and central Italy. On May 20, a magnitude 6 earthquake killed seven people and destroyed hundreds of buildings, including ancient churches and castles, and forced thousands of people to sleep outdoors in tents. Italian media said the latest earthquake caused more buildings to collapse.

Train services around Bologna, near Modena, were disrupted, media said, and schools and other public buildings had been evacuated as far south as Florence.   

"We felt a very strong tremor," said Raffaella Besola, a resident of Bologna.

The US Geological Survey said the epicentre of Tuesday's 5.8 magnitude earthquake, which struck at a depth of 9.6 km (6 miles), was less than 30 km (19 miles) from Modena, not far from where the quake hit just over a week ago.

Messages posted on Twitter and other social media suggested the tremor was felt across northern Italy. - Reuters