MILAN (AP) - GENOA, Italy (AP) -- Italian prosecutors focused their investigation into the Genoa highway bridge collapse on possible design flaws or inadequate maintenance, as the death toll rose Wednesday to 39 people and Italian politicians looked for someone to blame.
Fears mounted that another part of the Morandi Bridge, which was carved in two by the collapse of its midsection during a violent storm Tuesday, could also come crashing down. That prompted authorities on Wednesday to widen an evacuation zone around the bridge, forcing some 630 people out of apartments in nearby buildings.
Transportation and Infrastructure Minister Danilo Toninelli raised the possibility that the evacuees may never again live there, saying the need to rebuild a new bridge on the city's key artery could require the destruction of nearby residential buildings.
On Tuesday, just as many Italians were driving to vacation destinations on the eve of Italy's biggest summer holiday, a huge stretch of the 51-year-old bridge collapsed, sending over 30 cars and three trucks plunging up to 45 meters (150 feet) to the ground. The section that collapsed was 80 meters (260 feet) long.
Still dazed or shaken, survivors on Wednesday recounted their brushes with death.
One truck driver provided a dramatic account, including a description of how an emblematic green truck seen in photos worldwide stopped just short off the abyss and of police heroism as the bridge crumbled.
The truck driver identified only as Idris said the green truck was saved thanks to a car that passed it, forcing its driver to brake slightly. The car plunged off into the chasm.
"That truck driver is the luckiest in the world," Idris told Sky TG24. "He should have fallen in but there is a car that passed him ... he braked right where the bridge was broken."
Idris credited police for arriving quickly and moving some 150-200 people who were on the bridge to safety in a tunnel -- then adding a real risk by returning to the bridge with car keys to bring some of the vehicles to safety.
As this crippled Mediterranean port city of 600,000 reeled from the tragedy, about 1,000 rescue workers kept up the search for victims, picking through tons of broken concrete slabs, smashed vehicles and twisted steel. At least two bodies more were pulled out.
The tons of debris that rained down from the bridge landed in a dry stream bed, along a railroad track or crashed down perilously close to apartment buildings. At one point, Sky TG24 said, residents were temporarily blocked from even returning to their homes briefly to grab essential documents, medicine or other necessities.
After the search for bodies ends, tons of debris needs to be cleared away as soon as possible. Genoa is a flood-prone city, and authorities warned that all the concrete in the dry riverbed could become a dam within hours if heavy rains arrived.
Civil protection chief Angelo Borrelli confirmed Wednesday that 39 people had died and 15 were injured. Interior Minister Matteo Salvini said three children were among the dead. Four French citizens traveling to a music festival and two Albanians were also reported killed.
Genoa Prosecutor Francesco Cozzi told reporters the investigation into the collapse was focused on human causes, specifically the possibility of inadequate maintenance or a design flaw in the bridge's construction.
"I don't know if there is responsibility. For sure it was not an accident," he said.
Asked if authorities had been given any warning that the bridge -- a key link between two major highways, one headed toward France and the other to Milan -- could be dangerous, Cozzi indicated that no serious safety concerns had reached his office before the collapse.
Otherwise "none of us would have driven over that highway 20 times a month, as we do," Cozzi said.
A 20 million-euro ($22.7 million) project to upgrade the bridge's safety had already been approved, with public bids to be submitted by September. According to the business daily Il Sole, the improvement work involved two weight-bearing columns that support the bridge -- including one that collapsed Tuesday.
The 1967 bridge, considered innovative in its time for its use of concrete around its cables, was long due for an upgrade, especially since the structure was more heavily trafficked than its designers had envisioned.
One construction expert, Antonio Brencich at the University of Genoa, had previously called the bridge "a failure of engineering."
Other engineers, noting that the bridge was 51 years old, said corrosion and decades of wear-and-tear from weather could have been factors in its collapse.
The Italian CNR civil engineering society said structures as old as the Morandi Bridge had surpassed their lifespans. It called for an ambitious plan to repair or replace tens of thousands of Italian bridges and viaducts built in the 1950s and 1960s.
Italian politicians, for their part, were busy pointing fingers at possible culprits.
Italy's deputy premier, Luigi Di Maio, blamed the bridge collapse on a lack of maintenance by the private company that operates many of the nation's toll highways. Speaking in Genoa, Di Maio said he was looking at revoking highway concessions.
"Instead of investing money for maintenance, they divide the profits. And that is why the bridge falls," Di Maio said of the holding company that controls Autostrade Per L'Italia.
Di Maio, who leads the anti-business 5-Star Movement that is part of Italy's coalition government, also took a swipe at the Benetton group, which controls Autostrade SRL through its Atlantia holding company. He blamed previous Italian governments of turning a blind eye to the health of the nation's toll highways because of their desire for political contributions from those companies.
Autostrade controls 3,020 kilometers (1,876 miles) of Italian highways.
Toninelli, the infrastructure minister who is also from the 5-Star Movement, threatened in a Facebook post that the state, if necessary, would take direct control of the highway if the contractor couldn't properly care for it. He said his ministry had started procedures so Autostrade SRL could be fined up to 150 million euros ($170 million) and demanded that its leaders resign.
State radio reported Wednesday that some 5-Star lawmakers in 2013 had questioned the wisdom of an ambitious, expensive infrastructure overhaul program as possibly wasteful, but a post about that on the Movement's site was removed quickly after the bridge's collapse.
Salvini, too, wasted no time in trying to shift the blame away from Italy's new populist government. Hours after the bridge collapsed, he vowed not to let European Union spending strictures on Italy, which is laden with public debt, stop efforts to make the country's infrastructure safe.
D'Emilio reported from Rome and Barry from Milan. Simone Somekh in Rome and Angela Charlton in Paris contributed.