Quake-struck central Italy was hit by several aftershocks early Friday, the US Geological Survey reported. The strongest aftershock hit at 0428 GMT with a magnitude of 4.7.
The epicentre was about five kilometres north-west of the town of Amatrice, which was already badly damaged by Wednesday's magnitude-6 earthquake.
Several houses in the town centre collapsed, the Italian news agency ANSA reported. There were no immediate reports of casualties.
At least 250 people were killed in the massive earthquake that razed three towns to the ground in central Italy early Wednesday. Authorities have said they expect the count to rise.
Rescue efforts have been complicated by hundreds of aftershocks.