L'AQUILA, Italy (AP) — A strong aftershock sent firefighters and rescuers scrambling Tuesday morning from a collapsed dormitory where they have been working frantically to find university students trapped by the powerful earthquake that devastated this central Italian city.

As many as four students could be inside the building, officials said. Emergency workers were hunting for as many as 30 people pinned under rubble elsewhere in L'Aquila, a historic city of some 70,000 people that sits near the epicenter of Italy's worst quake in three decades.

Rescuers worked overnight inside the four-story dormitory and pulled two bodies from the rubble. They ran out, appearing confused, when the 4.9-magnitude aftershock hit at 11:26 a.m.

There have been a series of aftershocks since the 6.3 quake early Monday killed at least 179 people, injured more than 1,500 and left tens of thousands homeless. Tuesday's aftershock appeared strongest in L'Aquila, a city of Romanesque, Gothic, Baroque and Renaissance architectural treasures in a valley surrounded by the snowcapped Apennine mountains.

Two buildings in Pettino, a suburb of L'Aquila, collapsed following the aftershock, the news agency ANSA reported, citing fire officials. No one was believed to be inside either building.

The ground shook in the nearly leveled town of Onna, about six miles (10 kilometers) away, but caused no panic.

Rescuers in L'Aqulia returned to the rescue effort, scooping through piles of rubble with their hands and where possible, with cranes. Firefighters said they had pulled 100 people live from the rubble.

While the elderly, children and pregnant women were given priority at tent cities in the area, others were sleeping in cars or making their own arrangements to stay with relatives or in second homes out of the quake zone.