"The earthquake was very strong and heavily damaged the structures of many warehouses as well as thousands of tonnes" of the two cheeses, said Stefano Berni, head of a consortium that protects the Grana Padano designation.

"It's a very heavy loss, but there have been no casualties, which is a great relief at this worrying time," he told the ANSA news agency.

An initial estimate of 250 million euros ($320 million) is "very conservative," Berni said, adding that he hoped no further tremors would "further aggravate the state of the already highly damaged and fragile structures."

A wheel of the cheese can weigh up to 40 kilogrammes (90 pounds).

20 dead in tunnel blast in China: state media
Beijing (AFP) May 19, 2012 - Twenty people were killed in an explosion inside an under-construction expressway tunnel in central China's Hunan province on Saturday, state media said.

The blast happened in Zhuzhou city when a vehicle carrying explosives was unloading in the tunnel, the Xinhua news agency said, citing local authorities but providing few more details.

Four workers had been pulled out of the tunnel, including one in a critical condition, the report said.

China's roads are notoriously dangerous, with traffic laws and safety widely flouted. Bus operators often seek to cram as many people as they can into their vehicles to maximise profits and drivers hurtle down highways.

Last year alone, more than 62,000 people died in traffic accidents, state media said, citing police figures.

"The roof of my house has collapsed and I was told to come here, but I don't see where we can sleep," complained one man, who was among about 100 others seeking refuge in the gym, bemoaning the absence of beds and trying to keep warm under blankets.

Authorities evacuated about 3,000 people from the Emilia Romagna region, where a magnitude 6.0 quake struck early Sunday, killing at least six.

Most were evacuated from the Modena area, while 500 were asked to leave their homes in the area around Ferrara.

A local representative from the civil protection service, who spoke on condition of anonymity, said he was frustrated with the response to the disaster.

"We have not been told what to do yet. It's just confusion here," he said, clearly irritated. "We are waiting and keeping count of the people who are arriving."

He added that many houses were still spewing gas from leaks.

Survivors in the gym were relieved to be away from the quake's epicentre.

Speaking on a deserted basketball court, 38-year-old Angelo huddled with his wife and one-year-old.

"I was told that I can go home, but I am afraid. I have a baby and I don't want to have to re-live what happened overnight," he said.

"We will sleep here even if they don't bring us beds or anything. At least it's safe."

Angelo said his house shook so hard it was impossible to flee from it.

"When we were got on the street, it was like we were at sea, the ground was shaking," he said.

Several children were among the survivors, as well as two wheelchair-bound elderly women, a woman with a small dog and a chain-smoking man.

"I still have goosebumps," the man said. "When I felt the quake, I went to get my baby from the cradle but I couldn't find him -- with the shock, I did not understand that my wife had already taken him outside," the man said.

"I was screaming, I was desperate," he said, adding that he would sleep outside in case an aftershock jolted the gynasium.

The fatal quake was registered at 0204 GMT. Authorities said its epicentre was the commune of Finale Emilia, 36 kilometres (22 miles) north of Bologna, at a depth of only 5.1 kilometres (3.2 miles).

While many in the gym were upset at the lack of bedding, a small bar was offering sandwiches and crackers.

"At least they have given me something to eat here," one survivor said.