Residents of Italian towns devastated by an earthquake have been rattled by a series of aftershocks overnight, the strongest measuring 4.2, as Italy began a day of national mourning.

A day of national mourning will be held on Saturday, with flags to fly at half mast around the country for the dead.

A state funeral for 40 of the victims in the nearby town of Ascoli Piceno to be attended by Premier Matteo Renzi and President Sergio Mattarella.

Ahead the funeral, caskets were lined up in a gym where mourners have been bidding farewell to loved ones, kneeling, crying and placing their hands on flower-covered caskets.

The quake that struck before dawn on Wednesday took the lives of at least 281 people while 387 have been hospitalised for injuries.

Saturday’s early morning aftershock had a magnitude of 4.2, according to the Geological Service, while the Italian geophysics institute measured it at 4.

The civil protection department in Rome said 388 people were being treated for injuries in hospitals, and 40 of them were in critical condition.

An estimated 2,500 people were left homeless by the most deadly quake in Italy since 2009.

The earthquake-decimated historical area of Amatrice, Italy. Photo: AAP

The government has promised to rebuild the region, but some local people fear that won’t happen.

More than 1050 aftershocks have hit the area since the 6.2 magnitude quake early on Wednesday, bringing fresh damage to structures still standing.

These included a bridge leading to Amatrice, which had to be closed on Friday, further complicating the rescue operation.

The foreigners who died in the disaster included six Romanians, a Spanish woman, a Canadian, an Albanian and three British holidaymakers.