Earthquakes caused widespread damage and terrified residents in central Italy overnight but killed no one, two months after a strong quake left nearly 300 dead and razed villages in the same area.
Several people were slightly injured, but only a few needed hospital treatment, the Civil Protection Agency said.
In Visso, one of the larger hill towns hit, the mayor said most of the damage had been to buildings already weakened by the Aug. 24 earthquake.
Boulders tumbled down the valley into roads around Visso. Officials were restricting access to its historic center, awakening grim memories of the levelling of the hilltop town of Amatrice in August.
The three main overnight quakes came about two hours apart. Close to Visso, the rose-windowed facade of a late 14th century church, San Salvatore a Campi di Norcia, was reduced to rubble.
The first tremor measured magnitude 5.4, causing many people to flee their homes and the second was stronger at 6.1, according to the U.S. Geological Survey.
A 4.9 aftershock came a couple hours after that, and dozens of weaker ones followed.
"The first tremor damaged buildings, with the second one we had collapses," fire department official Rosario Meduri said.
He had come from southern Italy before Wednesday's tremors to help secure structures damaged by the August earthquake that hit some 50 km (30 miles) to the south.
The quakes were probably a continuation of seismic activity that began in August, Massimiliano Cocco from Italy's National Institute of Geophysics and Vulcanology told the Corriere della Sera newspaper.
The fact that the first earthquake was weaker than the second probably helped save lives because most people left their homes before the second, Interior Minister Angelino Alfano said on state radio.
The government said it set aside 40 million euros ($44 million) during a cabinet meeting on Thursday for immediate costs related to the earthquakes. Prime Minister Matteo Renzi planned to visit the area hit hardest later in the day.