ROME, Aug. 24 (Xinhua) — The death toll in a strong earthquake in central Italy has risen to 21, authorities said Wednesday.

The magnitude-6.0 earthquake hit the city of Rieti at 3:32 a.m. Thursday (0132 GMT), with a shallow depth of 4.2 km, according to the National Institute of Volcanology and Seismology.

Several powerful aftershocks followed, said the agency.

The temblor was strongly felt across the Lazio region and in Rome, the capital of the country.

Amatrice and Accumuli, two small towns in the Rieti province, were among the hardest hit, local media reported. Sergio Pirozzi, mayor of Amatrice, told local media that "most of the town is gone."

Five people were believed to have been killed in Amatrice.

At least two people were confirmed dead and a family of four, including two children, were trapped under rubble in Accumuli.

"Unfortunately, we expect the number of victims to rise as day breaks," Accumuli mayor Stefano Petrucci said.

Rescue teams and citizens were at work in the early morning, digging to find survivors as voices of people trapped under rubble could be heard, Ansa news agency reported.

Separately, authorities confirmed three victims in Pescara del Tronto, in the Marche region.

Italy's Civil Protection Agency said the earthquake was severe.

Civil Protection chief Fabrizio Curcio told a press conference in Rome early Wednesday that the earthquake could be compared to the strong earthquake that hit the city of L'Aquila in 2009, which left more than 300 people dead and thousands displaced.