Rescuers worked into the early morning hours Tuesday in hopes of finding survivors of a powerful earthquake that ripped through Italy's mountainous Abruzzo region, killing scores of people and leaving tens of thousands homeless. Tearful survivors, many of them clad in pajamas and blankets, watched as bodies were pulled from the rubble in the medieval city of L'Aquila, about 120 km (75 miles) northeast of Rome. The quake killed more than 150 people, L'Aquila's fire department said late Monday. Nearly 24 hours after the quake hit, authorities were still unsure how many people remained trapped in the wreckage. "We think maybe 70 to 100," said Francesco Rocca, a spokesman for the Italian Red Cross. "We still don't know the exact number. This is why we are still working very, very hard at the moment." Another body was found in the rubble of a student dormitory early Tuesday morning, and at least five other students were believed inside. But aftershocks hindered rescuers early Tuesday, and they have asked for additional equipment and expertise from Rome, authorities at the scene told CNN. Italy's Civil Protection agency reported at least 1,500 injured and 50,000 without shelter. "I can say there's hardly a building which was left without some sign of what has happened in the historical center of L'Aquila," Prime Minister Silvio Berlusconi said during a visit to the stricken region. "All the public buildings have been affected." Berlusconi said 4,000 people were working on the rescue effort. Civil defense officials said they are prepared to house up to 30,000 people, but many of those displaced have gone to hotels. Of the 150 dead, about 100 bodies have been identified, the officials said. Monday's earthquake was about 10 kilometers (6.2 miles) deep, the USGS said.