Dozens of aftershocks hit northeastern Italy overnight as thousands of jittery survivors spent the night in tent camps after the region's second killer quake in days.
Tuesday's quake killed at least 16 people and injured 350 just nine days after a similar disaster killed six people and left thousands homeless.
Residents in cities across northern and central Italy including Pisa and Venice rushed into the streets in panic when the quake struck 60 kilometres east of Parma at 07.00 GMT, as many were arriving for work.
Just a few hours later, already shaken residents endured a terrifying five-minute ordeal when the region was struck by three tremors of between 5.1 and over 5.3 magnitude, sparking panic and bringing down weakened buildings.
Rescue workers were searching for one person still missing on Wednesday.
A 65-year-old woman was the last person to be pulled alive from the rubble Tuesday night, after firemen heard her cries. She was saved by sheltering under a kitchen table as the five-storey building in the town of Cavezzo collapsed.
Workers at a destroyed precision mechanics factory near Modena
where three of their colleagues died, told how they ran for their lives as the ground shook, ripping the building in two and sending masonry crashing to the ground.
“Everything happened so fast, in about seven to eight seconds. I don't even remember. I ran out carrying the piece I was working on and I saw everything crumble,” said one worker who gave his name as Daniel.
“The quake was so violent,” he said, trembling with shock, adding that he feared being trapped in the shaking building.
As the dust began to settle in the moments following the quake, those who had made it to safety realised that three people - an Italian, as well as an Indian and a Moroccan - had been killed in the collapse.
“I'm grief-stricken, speechless. I have no tears left to shed,” Daniel added, saying he had worked with the dead men at the close-knit Meta factory in San Felice sul Panaro for years.
One victim had been living in a tent at a camp since the May 20 6.0-magnitude quake which left six people and around 7 000 living in makeshift dwellings, after many homes and historic buildings were reduced to rubble.
“I have to leave the building, we're being hit by a long, powerful tremor. I have to get out,” a civil protection agency spokesman in Mantua told AFP as one of the tremors struck.
“Everything's collapsed, it's chaos, buildings across the town are down,” a fireman in the tiny town of Cavezzo told Corriere della Sera newspaper.
Officials in the Emilia Romagna region said over 5 000 people had been evacuated from their homes, adding to the thousands already homeless after the May 20 quake.
The national geographics institute said the region had been hit overnight by a series of quakes, the strongest of which - 3.54
magnitude - was registered at 03.15 GMT, and many feared the nightmare was not over.
Monday “was the first night we'd spent back in our homes after the first quake. Then another one hit,” one resident told Italian television in Sant'Agostino, scattered with buildings with gaping holes in their sides.
Among the quake victims was a parish priest in the town of Rovereto di Novi who was killed by a falling beam after he went back into his church to save a Madonna statue.
Dust hung in the air in the picturesque towns of Carpi and Concordia, while in Mirandola rubble covered the Duomo floor and the roof gaped open to the sky.
In Mantua, the Ducal Palace - famous for a stunning collection of frescoes in the Wedding Room - was damaged, along with a number of historic churches.
“A new quake has hit the Emilia Romagna region, leaving victims, wounded people and damaged buildings in its wake,” Prime Minister Mario Monti said.
As the region took stock of the damage to national heritage treasures, there were calls for an investigation into why the wreckage was so extensive.
“It is natural to have earthquakes, it is not natural for buildings to fall down like this. It doesn't happen in other countries,” said Welfare Minister Elsa Fornero.
Pope Benedict XVI sent his condolences to the families of the victims.
The region has been hit by a series of quakes and aftershocks over the past two weeks. Authorities have registered at least 800
tremors since May 20.
The latest disasters struck just over three years after a 6.3-magnitude quake devastated the city of L'Aquila in central Italy in March 2009, killing about 300 people and leaving tens of thousands homeless. - Sapa-AFP