A young family of three was killed when a highway bridge in the Italian city of Genoa collapsed, claiming the lives of at least 35 people as they plummeted to the ground or were crushed by debris.

Roberto Robbiano, his wife Ersilia Piccinino, and their 7-year-old son Samuel all died when their car fell 150ft as the huge 260ft section of the 50-year-old Morandi bridge gave way about 11.30am on Tuesday.

Cars, tonnes of twisted steel and concrete debris fell into a river, railroad tracks and an industrial zone below, flattening vehicles and leaving rubble embedded in buildings.

The family from the town of Campomorone north of Genoa were on the busy arterial road west of the city that was bustling with traffic.

Robbiano, an electrician, married his wife in 2014 and frequently posted photos to his Facebook of his young son and the black-and-white family cat on adventures at home and on holiday.

Amateur football player Andrea Cerulli, the father of a young son, was killed on his way to work, according to friends who flooded social media with tributes after finding out about his death.

"Genoa Club Portuali Voltri rallying around Andrea's family, our associate, our friend, our colleague, victim of Ponte Morandi's tragedy," his football club wrote on its Facebook page.

The death of Luigi Matti Altadonna, 35, who also died crossing the doomed bridge prompted a heartfelt statement to his uncle from the mayor of his hometown of Borghetto.

"The municipal administration joins the pain of Giovanni, a model citizen and an exemplary volunteer of the Civil Protection Section of Borghetto, for the loss of his dear nephew in the terrible tragedy of Genoa," Mayor Borghettino Giancarlo Canepa said.

Altadonna was driving his work van over the bridge when it collapsed under him. Rescuers scrambled to free him from the wreckage but he could not be saved.

His relatives launched a desperate social media appeal to find him after he could not be reached, and he was later identified in hospital.

Two workers from waste management company Ammiu were crushed by falling debris as they worked on the ecological island of Campi below the bridge.

The company named one of them as Mirko Vicini, whose body was found in the evening despite hopes he may have not been at work that day and survived.

"The damages are invaluable but nothing compared to the pain for the lives lost," company director Tiziana Merlino said. The firm shut down work on the island indefinitely.

Finally, Mayor of Florence Dario Nardella confirmed that an unnamed boy was killed in the bridge collapse, but did not say if any of his family were also victims.

"Florence is gripped by the family of the Florentine boy who lost his life in the tragic collapse of the viaduct in Genoa and the loved ones of all the other victims," he said.

Genoa declared two days of mourning for Wednesday and Thursday.

Italian Prime Minister Giuseppe Conte said at least 26 people died in the collapse, contradicting an earlier report by local officials that 35 people were dead. However, this morning police said at least 35 had been killed.

Among the devastation, a handful of survivors were miraculously plucked from the "apocalyptic" wreckage and rushed to hospital - some falling in their cars about 46m to the ground below.

Photos showed firefighters winching survivors strapped into stretchers from among the boulder-sized pieces of concrete, before they were whisked away by emergency helicopters.

Witnesses said the bridge was hit by lightning seconds before it collapsed and was seen "wobbling", but engineers rubbished the idea that a bolt from above had anything to do with the disaster.

"It couldn't have been lightning. I don't see how that would be possible as it's reinforced concrete and it's certainly never happened before," Agathoklis Giaralis, deputy director of the University of London's Civil Engineering Structures Research Centre, told MailOnline.

He said the bridge, which was completed in 1967, must have been flawed in its construction, likely in the foundations, or suffered from extensive corrosion in its metallic parts.

"For such a bridge to collapse it has to be something serious that went unnoticed in maintenance and inspections," he said.

"It's an old bridge that was difficult to inspect from the start and doesn't have the redundancies that modern bridges do, so it is likely that one failure could lead to its collapse."

Dr Giaralis said the metal parts, particularly the cables, of a bridge like the Morandi are the weakest parts but this bridge didn't fail there - pointing to bigger underlying issues.

"Usually these fail due to corrosion and that a process that takes decades, and it is very unusual that something that can cause total collapse went unnoticed," he said.

"I would say that most probably something went wrong with the foundation or supporting ground rather than with the pier, the deck, or the cables."

Dr Giaralis said the bridge was fully loaded with cars and there was wind, which may have triggered the collapse but would not have been the underlying cause as both should not be an issue for a healthy bridge.

Engineering experts also warned two years ago that it would be more cost effective to knock the bridge down than to continue to repair the 'uneven' construction.

In the early 1990s, the suspension cables along the bridge had to be replaced, and further restructuring work was carried out in 2016.

In 2016, Antonio Brencich, associate professor of civil engineering at the University of Genoa warned that the Morandi Bridge's maintenance costs "are so exorbitant that it would be cheaper to build a new one".

"Right away the bridge manifested various problems, beyond the construction costs, which went over budget," he wrote in 2016.

"There are errors in this bridge. Sooner or later it will have to be replaced. I don't know when," he warned.

In the article, quoted by Il Tempo, Professor Brencich says issues with the bridge being uneven and 'semi-horizontal' had plagued the construction since the early 1980s.

In December 2016, Genoan newspaper Il Secolo XIX claimed maintenance of bridges in the area had been lacking funds because authorities "preferred to allocate more funds to new works".

The paper accused officials in the Liguria region of only making important restorations when issues with bridges had become obvious.

The disaster shocked the world but many locals feared the bridge would collapse for years and held their breath every time they crossed the vital arterial road.

"The state of the bridge always concerned us. Nobody has ever crossed that bridge with a light heart," Genoa resident Elizabeth told the BBC.

"Everybody has always done it praying that the bridge wouldn't fall down. Today that happened."

There were also concerns the Italian mafia could have contributed to the bridge's collapse by their construction companies being involved in maintenance work - including shoring up the foundations.

"Mafia-related companies are known to have infiltrated the cement and reconstruction industries over the decades and prosecutors have accused them of doing shoddy work that cannot withstand high stress," Canada's Globe and Mail wrote.

"The Mafia is notorious for nabbing reconstruction contracts after earthquakes and cutting corners."

Franco Roberti, then head of Italy's anti-Mafia directorate, said in 2016 that mafia-related companies should not be able to participate in earthquake reconstruction work for that reason.

"There are risks; it is useless to hide it," he told Italy's La Repubblica newspaper at the time. "The risk of infiltration is always high. Postearthquake reconstruction is a tasty morsel for criminal organizations and business interests."

One witness said he saw the 50-year-old structure "wobbling" minutes before it gave way as dramatic footage showed it being struck by lightning seconds before it crumbled.

"It was just after 11.30 when we saw lightning strike the bridge and we saw it going down," eyewitness Pietro told Italy's Ansa news agency.

One unnamed witness said: "We heard an incredible roar and first we thought it was thunder very close by.

"We live about three miles from the bridge but we heard a crazy bang... We were very scared... Traffic went completely haywire and the city was paralysed."

Laurie Merchant, who was in Genoa at the time, told MailOnline: "The storm this morning was something else: very heavy rain and relentless. There was thunder like never before which sounded like a cannon. I was about five minutes from the bridge and I heard a loud crumbling when it went down.

"All you can hear in the city is the sirens of the emergency vehicles going non-stop from the bridge to the hospital.

"The air ambulance has been hovering most of the day. There are huge numbers of people outside the hospital and on the main shopping street there are two vans for people to donate blood."

Incredibly, four people have been pulled alive from cars found in the mangled ruins of the bridge while two warehouses below the structure were empty having been closed for the summer holiday.

Dramatic photos shows how a green truck had stopped just short of the gaping hole in the bridge, which was built on the A10 toll motorway in northwestern Italy in the 1960s.

The exact cause of the disaster, the latest in a string of bridge collapses in Italy, is not yet clear but Transport Minister Danilo Toninelli said it showed the dilapidated state of the country's infrastructure and a lack of maintenance, adding that "those responsible will have to pay".

"There has not been sufficient maintenance and checks, and safety work for many bridges and viaducts and bridges in Italy constructed, almost all, during the 1960s," he said.

Toninelli said the operator of the section of highway including the bridge claimed maintenance work was up to date.

However, he added a €20 million ($35 million) bidding process for significant safety work on the bridge was coming up.

The bridge operator said there was no way to predict that the structure would come down.

Autostrade's Genoa area director, Stefano Marigliani, said: "The collapse was unexpected and unpredictable.

"The bridge was constantly monitored and supervised well beyond what the law required. There was no reason to consider the bridge dangerous."

His deputy Edoardo Rixi added: "It's not acceptable that such an important bridge... was not built to avoid this kind of collapse."

The CNR civil engineering society is calling for a 'Marshall Plan' to repair or replace tens of thousands of bridges in Italy that have surpassed their lifespans, having been built in the 1950s and 1960s with reinforced concrete.

The group said the bridges were built with the best-known technology of the time, but that their working lifespan is 50 years.

It added that in many cases, the cost to update and reinforce the bridges is more than it would cost to destroy and rebuild them.

The CNR called for a major programme to replace most of the bridges with new ones that would have a lifespan of 100 years.

It cited previous collapses, including one in April 2017 in the northern province of Cuneo that crushed a police car, though the officers and the driver they had pulled over in a traffic stop heard the creaking noise and got out of the way in time.

Another was an overpass in the northern city of Lecco that collapsed under exceptional weight, crushing a car and killing the driver.

Italy's anti-establishment government which took office in June has pledged to increase public investments and lobby the European Commission to have the extra spending excluded from EU deficit calculations.

"The tragic facts in Genoa remind us of the public investments that we so badly need," said Claudio Borghi, economics spokesman of the right-wing League party, which governs with the 5-Star Movement.

The office of Prime Minister Giuseppe Conte said he was heading to Genoa in the evening and would remain there on Wednesday. Defence minister Elisabetta Trenta said the army was ready to offer manpower and vehicles to help with the rescue operations.