6.2 magnitude quake struck central Italy early on Wednesday near the town of Norcia, the U.S. Geological Survey said.
Strong tremors woke residents in the capital Rome, some 170 km (105 miles) from the epicentre of the quake, which occurred at 3.36 a.m. (0136 GMT).
The spokesman for the Italian fire department, Luca Cari, said they had received reports of buildings being damaged, but had no further details.
The USGS initially reported the magnitude of the quake at 6.4, saying it was very shallow, only 6.2 miles (10 km) deep.
"It was the worst (quake) of my life," said Matteo Berlenga after leaving his house near Gubbio in the central Italian region of Umbria when the earthquake struck.
Prime Minister Matteo Renzi's spokesman said on Twitter that the government was in touch with the country's civil protection agency.
The central Italian town of Amatrice was badly damaged by the quake, with people trapped under the rubble, the town's mayor said.
"The roads in and out of town are cut off. Half the town is gone," Sergio Pirozzi, mayor of Amatrice, told RAI state television."There are people under the rubble. There's been a landslide and a bridge might collapse."
Italy's Civil Protection agency said the earthquake was "severe" and there had been reports of damage, while a refuge on Gran Sasso mountain said on its Facebook page that a large piece of rock collapsed in the quake.