NORCIA, Italy (AP) — Italy's premier pledged Monday to find temporary housing for all those displaced by a series of powerful earthquakes in a central mountainous region, as the nation's strongest temblor in 36 years pushed those needing assistance to more than 15,000.

Sunday morning's quake with a magnitude 6.6 caused no deaths or serious injuries, largely because most fragile city centers had already been closed because of previous damage and many homes had been vacated.

But it did complicate quake relief efforts in a zone that was still coping with the aftermath of an August quake that killed nearly 300 in the same region, and a pair of powerful aftershocks last week that also claimed no lives.

Civil protection officials said they expect the number of people needing assistance to continue to rise, as it doesn't count the many people who slept in vehicles or made other arrangements and are likely to seek help. Temperatures overnight reached near freezing, and officials have expressed concern for the many elderly residents of these mountain communities.

"We cannot have tents for some months in the mountains, under the snow," Premier Matteo Renzi wrote in a message on Monday. "There are enough hotels for everyone. But many of our compatriots don't want to leave their lands, not even for some weeks."

Many people have been moved to coastal areas, where summer resort hotels are mostly idle, and other zones away from the quake. But there are increasing reports of residents resisting in the belief that if their homes have so far resisted, that they remain the safest place to be.

In the town of Norcia, closest to the epicenter, firefighters were taking people back to their homes early Monday to retrieve belongings. They were given helmets as protection, and taken in in small groups as they arrived. The ground continued to shake overnight with at least two jolts above magnitude 4.

"We were inside our home and luckily the house handled it," said Emanuela Spanicciati, one resident of Norcia. "And that allowed us to get out into the streets. There were various injured people, but in the end we were lucky."

Renzi said the fact that there were no deaths "gives us enormous relief. But the damage to the housing stock, as well as economic, cultural and religious treasures is impressive. These villages are the identity of Italy. We must reconstruct them all, quickly and well."

Many of the towns struck are of historic significance, including Norcia, where a Benedictine cathedral collapsed, leaving just a facade.

Colleen Barry reported from Milan.