A series of aftershocks hit Italy on Monday after a 5.9-magnitude quake killed seven people and injured some 50 others on Sunday.

Over 115 aftershocks, some of which powerful, shook the epicenter area located between the central cities of Ferrara and Modena, according to Italy's National Institute of Geophysics and Volcanology (INGV).

"Other quakes that we expect to occur in the area will be of a comparable magnitude to the one happened last night," INGV seismologist Concetta Nostro told Xinhua.

"However, damages do not depend uniquely on magnitude but especially on the vulnerability of buildings and structures, therefore we cannot be certain that there will not be further harm," she said.

As various homes were damaged and other shakes were expected to occur, over 4,000 people reportedly spent the night in public structures, hotels or tents as suggested by civil protection teams despite strong rainfall hitting the area for many hours.

Local police warned of possible acts of profiteering after a man dressed like a guard was discovered while he was trying to steal from empty homes.

The artistic damage was "considerable", local authorities said, as many monumental centuries-old buildings and churches in central Italy collapsed or showed serious loss.

The quake was also felt in various artistic cities in northern Italy such as Venice and Mantua, the latter being hit in its renowned Ducal Palace, whose roofs and walls were slightly damaged.

"This fact presents again the problem of Italy's artistic patrimony, that must be protected, as it does not only represent our historical and cultural treasure, but is also a fundamental economic resource of our country," said environment minister Corrado Clini.

Clini added Italy is a seismic country, however "after recent major shakes, our territory's maps need to be revised as some quakes occurred in areas that were considered not at risk."

Italian Prime Minister Mario Monti, who was in the U.S. attending a NATO summit, returned earlier on Monday due to "incumbent emergencies" in the country.

According to local media, the government will declare a state of emergency during its first meeting of the week scheduled for Tuesday.