The death toll of a 5.9-magnitude earthquake that hit northern Italy in the early hours of Sunday morning has risen to seven, local media said.

A collapsed oratory is seen at San Carlo in the Emilia-Romagna region, northern Italy, May 20, 2012. [Xinhua]

The seventh victim of the earthquake was an 86-year-old female, who felt ill after the strong shock and died from a stroke after being sent into hospital.

Four night workers, including a young foreign migrant, died in the collapse of three factories near the city of Ferrara in the central Emilia Romagna region.

An over-100-year-old lady was killed in her bed and another 37-year-old woman died by heart attack during the quake, according to local media.

At least 50 people were injured in the earthquake, while about 3,000 displaced people who left their house which were considered not safe enough for living would spend the next nights in hotel, public structures or tents set up by rescue men.

According to Italy's National Institute of Geophysics and Volcanology (INGV), the earthquake had its epicenter between the cities of Ferrara and Modena at a depth of 6.3 km. In several Italian regions including Tuscany, Piedmont and Lombardy, the shock was felt without causing great loss.

Italian Prime Minister Mario Monti, who is in the United States attending a NATO summit, decided to return early and would arrive in Italy on Monday morning.

In the most hit town of Sant'Agostino, the municipality was demolished and historic buildings were strongly damaged and evacuated.

One five-year-old girl was rescued after remaining trapped in debris following the quake, a police officer, Giampiero Natoli, told local media.

Local authorities ordered residents not to get close to historic buildings, while the eldest and seriously sick people were rushed to nearby hospitals for precaution.

Franco Gabrelli, head of Italian Civil Protection, said the priority is that people with house damaged in the earthquake and considered not safe for living can spend night in "acceptable conditions," after he finished an emergency meeting held in Ferrara.

"Our municipal operation centers are collecting people's requests, we will check availability of hotels and meanwhile we are preparing a plan for setting up the tents," he said.

Asked about the risks of aftershocks, Gabrelli said it is common that a big earthquake is followed by other shocks.

A powerful aftershock measuring magnitude 5.1 hit the same area after the 5.9-magnitude earthquake.

According to the INGV, the powerful aftershock had its epicenter between the cities of Ferrara and Modena in the region of Emilia Romagna, with a depth of 4.7 km.

The INGV said more than 50 aftershocks, most of them below magnitude 4.0, followed the 5.9-magnitude one.

The artistic damage was considerable, as many monumental historical buildings were hit, said Paola Gazzola, civil protection councilor of Emilia Romagna region.

In 2009, an earthquake of 6.3 magnitude killed nearly 300 people in the Italian central city of L'Aquila.