ROME — An earthquake, believed to be the strongest to hit Italy since 1980, struck the center of the country on Sunday, four days after two back-to-back quakes severely damaged buildings and left thousands homeless in the area. The temblor on Sunday also caused fresh damage to the towns destroyed by a quake that killed nearly 300 people in August.
The quake, which had a magnitude of 6.5, according to Italy’s national geophysical and volcanology institute, struck at 7:41 a.m. with its epicenter near Norcia. It was felt as far away as Bolzano in northern Italy and Puglia in the south, according to Italian news reports.
Most of the towns in the area had already been evacuated after the recent seismic activity, so there were no immediate reports of deaths.
About 20 people were injured but none killed, said Fabrizio Curcio, the head of Italy’s civil protection department. “It was an important earthquake,” he said.
Helicopters were taking people to hospitals because some roads had been closed off, Mr. Curcio said. Search-and-rescue teams were converging on the area, he added, and mayors were verifying the conditions of residents in smaller hamlets.
As night fell, emergency teams worked to transfer residents of the stricken areas to temporary dormitories and hotels in outlying areas, overcoming the resistance of those who preferred to remain near their homes, Mr. Curcio said.
“This was a 6.5 — we haven’t had an earthquake of this magnitude since 1980 — so there are a series of controls we have to carry out,” he said, adding that people would be assisted better outside the earthquake areas.
Electrical power was out for many thousands of residences, many roads were blocked by debris or cracks, and several sections of the Via Salaria, the most important highway in the area, were not accessible, Mr. Curcio said. Emergency workers were preparing to work through the night to clear roads of debris.
“It will be a difficult night,” Mr. Curcio said after meeting with the mayor of Norcia, Nicola Alemanno, and Vasco Errani, the government’s point man for the earthquake reconstruction program in Norcia.
Mr. Curcio said he hoped people would not spend the night in their cars or in makeshift camps and would opt for more stable accommodations. “There is no reason to suffer,” he said.
Mr. Alemanno estimated that at least 3,000 residents of the town had been left homeless. Other mayors were still tallying numbers of those left homeless in their own towns.
Mr. Errani, who was appointed after the August quake, said Sunday’s earthquake had “changed the scenario, and even more the spirit and the soul of people,” he said.
“We must remain calm to face the situation,” he added.
Aftershocks continued throughout the day, and the geological institute registered about 200 in the first 10 hours after the morning 6.5 quake, at least 15 of them with a magnitude measuring over 4.
The mayor of Rome, Virginia Raggi, ordered schools to remain closed Monday to allow for checks on their stability.
At a news conference, Prime Minister Matteo Renzi vowed to rebuild damaged areas. “We will rebuild everything — homes, churches, businesses,” he said.
Italy has been urging the European Commission to give it more leeway in meeting targets for its budget deficit, citing greater costs incurred by its response to the migrant crisis and to the fallout of the earthquakes.
The Italian government allocated 40 million euros, about $44 million, to the stricken zones after Wednesday’s quakes, and on Sunday Mr. Renzi said more would be set aside to deal with the fresh damage. “We will broaden the crater zone so no town must fear it might be left out,” he said.
“We can’t give back a smile to those who in this moment think they have lost everything,” said Mr. Renzi, who noted that the earthquake had been felt by many Italians.
He called on citizens to be strong and show solidarity. “Italy has its limitations and defects, but in these circumstances it gives the best of itself,” he said.