The death toll in a deadly earthquake in Italy has risen to 159, the Italian Civil Defence said Thursday.

The Italian Civil Protection Unit said in a statement “So far death toll stands at 159”, adding it feared the death toll would rise.

Flags will fly at half-mast outside the Italian prime minister's office Wednesday and Thursday for the victims of the earthquake.

Earlier, the Italian Civil Protection Department said the hardest-hit were Lazio town of Amatrice and nearby Accumoli.

Italian news agency ANSA reported numerous victims were still trapped under the rubble in Accumoli, Amatrice and Pescara del Tronto following the earthquake that struck at 3.36 a.m. local time (1336 GMT) and was followed by several aftershocks.

The U.S. Geological Survey said the 6.2-magnitude tremor struck at a shallow depth of 10 kilometres (six miles) southeast of Norcia – a town in Perugia, central Italy and occurred as a result of shallow normal faulting on a northwest-southeast oriented fault line in the Central Apennines.

ANSA quoted Renzi as vowing to “leave no one on their own – not one family, one town or one village,” before visiting the scene.

“The priority right now is to dig,” he said.

UN Secretary-General Ban Ki-moon offered his “deepest condolences” and added that “the United Nations stand ready to offer its support should that be requested.”

In a call with Italian President Sergio Mattarella, U.S. President Barack Obama offered American assistance with recovery efforts, the White House said.

But spokesman Josh Earnest said due to Italy’s experience in responding to major quakes “it is not clear to me at this point that any of those offers have been taken up.

“That frankly is a testament to the expertise of the Italians in responding to situations like this, but if our friends in Italy need our help, particularly in dealing with a situation like this, you can rest assured that we're going to provide it,” he told reporters.

Christos Stylianides, EU commissioner for humanitarian aid, said in a statement: “The EU is ready to help.

“At the moment, the Commission's Emergency Response Coordination Centre is closely monitoring the situation and has already been in contact with the Italian civil protection authorities during the night regarding any help which could be requested,” he added.

In comments reported by ANSA, Pope Francis addressed 11,000 faithful in the Vatican’s St. Peter’s Square and said he felt “great pain” over the deaths, adding he was with all those “who have lost loved ones and those who still feel shaken by fear.”

The Central Apennine region has experienced several significant quakes, including in April 2009 when a magnitude-6.3 tremor struck near the town of L’Aquila and killed at least 295 victims, injured more than 1,000 and left approximately 55,000 homeless.

•Text extracted from an Anadolu Agency report. Photo of rescuers at work after the Italy earthquake courtesy of Al Jazeera.

Update news