No deaths were known to have been caused by the latest temblor, which took place at 7:40 am (0640 GMT) in the Sibillini park, a rugged mountain area straddling the Marche and Umbria regions about 120 kilometres north-east of Rome, according to the Italian National Institute of Geophysics and Vulcanology (INGV).
The INGV had earlier estimated it at 6.1 magnitude.
"At the moment we have no news of victims," the head of the civil defence agency Protezione Civile, Fabrizio Curcio, said in a press conference.
"Dozens of people were slightly injured, except one person who is reported to be more serious," Curcio said, adding that there were "several (building) collapses" and extensive road closures.
Traffic was disrupted, forcing emergency services to evacuate the injured by helicopter, Curcio said.
Nevertheless, casualties were limited as many towns and villages in the affected area had already been evacuated after 5.4 and 5.9-magnitude quakes on Wednesday, which were followed by hundreds of after shocks in the following days.
"Everything has collapsed, I see cloud of smoke, it is a disaster, a disaster," the mayor of Ussita, an affected village, was quoted as saying by the ANSA news agency.
ANSA also said that the 14th-century San Benedetto Basilica and the Cathedral of Santa Maria Argentea collapsed in Norcia, a well-known medieval town in Umbria where people could be seen huddling in squares and kneeling in prayers.
Earlier this week, no earthquake-related deaths were reported, save for a fatal heart attack possibly triggered by shock. In addition, one person was hospitalized with a broken thighbone and three people suffered slight concussions.
The latest temblors took place about 30 kilometres north of Amatrice, the flash point of the 6-magnitude earthquake that struck on August 24, killing 298 people.
Sunday's earthquake could be felt hundreds of kilometres away, as well as in Rome, where two central Metro lines were halted by the tremor, causing delays, according to the city's transit network ATAC.