People walk past a collapsed building, after an earthquake, in Cavezzo near Modena. Photo: REUTERS/Giorgio Benvenuti

Just over a week after a devastating earthquake hit Italy's northern Emilia Romagna region, killing seven people, the same area was struck by a slightly less powerful, and yet more deadly aftershock.

At least 10 people were believed to have died, most of them workers at local factories, in Tuesday's tremor.

And as rescue and relief efforts were underway, several strong aftershocks continued to shake buildings and spread more fear among local inhabitants.

It all began at around 9 am (0700 GMT).

News television channel Sky TG24 had just finished airing a report on conditions at a tent-camp for survivors of the May 20 earthquake in the town of San Felice sul Panaro. The broadcast briefly switched to another news item, but then abruptly returned to images of the camp.

Several people could be seen running out of the neat row of blue tents, some of which appeared to be shaking. A loud rumbling noise could be heard in the background.

The main 5.8 magnitude aftershock had just struck. In the next hours it was followed by several others, including at least one topping magnitudes of 5.

According to Italy's National Institute of Geophysics and Vulcanology, the main aftershock's epicentre was in Mirandola, near the city of Modena – not far from Ferrari's headquarters in Maranello.

Initial reports did not mention victims, but a more serious picture soon emerged.

“Some people are buried under rubble ... at this stage I cannot say more,” the mayor of San Felice sul Panaro, Alberto Silvestri, said about hour after the 9 am aftershock.

Subsequent television images showed flattened factories and warehouses, and piles of rubble where buildings – some damaged in the May 20 earthquake – had now given way completely.

As with the earthquake 10 days before, San Felice sul Panaro appeared to be one of the worst-hit areas on Tuesday.

At least three workers at a local factory where among the dead, local Carabinieri commander Salvatore Iannizzotto said.

But other areas in Emilia Romagna were also counting their loss.

A woman was killed after she was buried in rubble when a furniture factory collapsed in Cavezzo, near Modena.

And two workers died when another factory collapsed in San Giacomo Roncole, near Mirandola, the ANSA news agency reported

There was also much confusion.

Officials denied an initial report – posted on the online edition of the Gazzetta di Modena local newspaper – that the parish priest in the town of Carpi had died.

In Rome, Prime Minister Mario Monti held an impromptu news conference in which he said increased efforts were underway “to guarantee” safety conditions in the quake-hit areas. He did not immediately provide more details.

The government declared a state of emergency following the May 20 earthquake, which also left more than 5 000 people homeless.

The government had already set aside €50 million ($64m) for relief efforts, including securing damaged buildings and roads, while Monti had told survivors that the government was also considering tax breaks to help them cope with the damage.

But the impact of Tuesday's aftershock threatened to increase the burden faced by local people and businesses in a region which lies in the fertile Po Valley. Here, thousands of small- and medium-sized enterprises – many of them producing export-orientated renowned goods such as Parmesan cheese and balsamic vinegar – are located.

“This territory is so important, so special and so productive for Italy,” Monti said Tuesday.

“I invite all citizens to have faith. The commitment of the state aims to guarantee that everything will take place in the best and most efficient way,” he added. – Sapa-dpa