MILAN — A highway bridge collapsed Tuesday in the Italian city of Genoa during a violent storm, sending vehicles plunging 45 meters (nearly 150 feet) into a heap of rubble. Authorities said at least 20 people were killed, although some people were found alive in the debris.

A huge section of the Morandi Bridge fell at midday over an industrial zone, sending tons of twisted steel and concrete onto warehouses below. Photos from the Italian news agency ANSA showed a massive gap between two sections of the bridge.

The head of Italy’s civil protection agency, Angelo Borrelli, said up to 35 cars and at least three trucks were on the 80-meter (260-foot) section of the span that collapsed.

Hundreds of firefighters and emergency officials were searching for survivors in the rubble with heavy equipment. At least four people were pulled alive from vehicles under the bridge, ANSA reported.

Video of the collapse captured a man screaming: “Oh, God! Oh, God!” Other images showed a green truck that had stopped on the bridge just short of the edge and the tires of a tractor trailer in the rubble.

There was confusion over the death toll, which changed several times during the day.

Civil protection authorities said 20 were killed and 16 were injured, at least 10 of them severely, based on multiple verifications from the prefecture’s office. But Genoa Mayor Marco Bucci told Sky TG24 that the number of dead was above 25 and that 11 injured were pulled from the rubble. Two other officials earlier put the toll at 22 dead with 13 injured but said it was expected to rise.

Borrelli told a news conference in Rome that the dead appeared to all have been in vehicles that fell.

One man who was standing under the bridge in front of his truck when the span collapsed called it “a miracle” that he survived. The middle-aged man, who did not give his name, said the shockwave sent him flying over 10 meters (33 feet) into a wall, injuring his right shoulder and hip.

“I was in front of the truck and flew away, like everything else. Yes, I think it’s a miracle. I don’t know what to say. I’m out of words,” he said, walking away from the site.

The disaster occurred on a highway that connects Italy to France, and northern cities like Milan to the beaches of Liguria. The Morandi Bridge connects the A10 highway that goes toward the French Riviera and the A7 highway that continues north toward Milan. Inaugurated in 1967, it is just over a kilometer (.6 miles) long.

The collapse came on the eve of the Italian summer holiday of Ferragosto, which marks the religious feast of the Assumption of Mary. It’s the high point of the season, when most businesses are closed and Italians head to the beaches or the mountains. That means traffic could have been heavier than usual on the Genoa highway.

The design of the bridge has been criticized in the past. Antonio Brencich, a professor specializing in reinforced concrete construction at the University of Genoa, called the span “a failure of engineering” in an interview in 2016.

“That bridge is wrong. Sooner or later it will have to be replaced. I do not know when. But there will be a time when the cost of maintenance will be higher than a replacement,” he told Italian media Primocanale.

Other engineers said corrosion or weather conditions could have been part of the cause.

“As this reinforced and pre-stressed concrete bridge has been there for 50 years, it is possible that corrosion of tendons or reinforcement may be a contributory factor,” said Ian Firth, former president of The Institution of Structural Engineers, a London-based international network. He called the bridge “an unusual design.”

Mehdi Kashani, an associate professor in structural mechanics at the University of Southampton in the U.K., said maintenance issues and pressure from “dynamic loads,” such as traffic and wind, could have resulted in “fatigue damage in bridge components.”

Borrelli said highway engineers were checking other parts of the bridge and that some areas were evacuated as a precaution. He said they were still trying to figure out the cause of the collapse.

“You can see there are very big portions of the bridge (that collapsed). We need to remove all of the rubble to ascertain that all of the people have been reached,” he said. More than 300 rescue workers and canine crews were on the scene.

“Operations are ongoing to extract people imprisoned below parts of the bridge and twisted metal,” he said.

Transportation Minister Danilo Toninelli called the collapse “an enormous tragedy,” adding that if negligence played a role, “whoever made a mistake must pay.”

Toninelli said the company that has the concession to operate that section of highway said its maintenance on the bridge was up to date and no work was being done at the time of the collapse. But he added that they were about to launch a 20 million euro ($22.7 million) bidding process for significant safety work on the bridge.

“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.

Since getting the job two months ago, Toninelli said he has asked for updates on the state of all bridges and viaducts in Italy. Many are operated by outside contractors.

French President Emmanuel Macron, meanwhile, offered his country’s help in a phone call with Italian Prime Minister Giuseppe Conte, who traveled to the site.

It was the second deadly disaster on an Italian highway in as many weeks.

On Aug. 6, a tanker truck carrying a highly flammable gas exploded after rear-ending a stopped truck and getting hit from behind near the northern city of Bologna. The accident killed one person, injured dozens and blew apart a section of a raised eight-lane highway.