Rome, May 21 (IANS): The toll from a 5.9-magnitude quake in northern Italy rose to seven Monday.

The seventh victim of Sunday's 5.9-magnitude tremor was an 86-year-old woman who died from a stroke after the quake, Xinhua reported.

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

A 100-year-old woman was killed in her bed and another 37-year-old woman died of a heart attack during the quake.

At least 50 people were injured, and about 3,000 people were displaced from their homes.

According to Italy's National Institute of Geophysics and Volcanology (INGV), the quake epicentre was located between the cities of Ferrara and Modena at a depth of 6.3 km.

The tremor was felt in Tuscany, Piedmont and Lombardy regions.

Prime Minister Mario Monti, who is in the US to attend a NATO summit, decided to return early and was expected to arrive in Italy Monday morning.