An Italian engineering professor appeared to predict the Morandi Bridge disaster two years ago, warning it would be cheaper to just build a new one.
Italy's Prime Minister Giuseppe Conte said 26 people were killed and 15 injured after the highway bridge, in the northern port city of Genoa, suddenly collapsed.
In 2016, Antonio Brencich, associate professor of civil engineering at the University of Genoa, warned it would cost more to repair the "uneven" construction, rather than just knock the bridge down.
He said maintenance costs "are so exorbitant that it would be cheaper to build a new one".
"The Morandi Bridge is referred to as a masterpiece of engineering. In reality it is a bankruptcy," he said in an interview with Italian TV channel primocanale.it. "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 maintenance costs will exceed those of reconstruction, and then we will have to proceed with the replacement."
The exact cause of the collapse remains unknown.
In December 2016, Genoan newspaper Il Secolo XIX claimed bridge restorations were underfunded because authorities "preferred to allocate more funds to new works".
The highway had already undergone significant maintenance in the 1980s and 1990s. In a statement following the incident, Italy's motorway operator Autostrade said the bridge "dates back to the 1960s" and "maintenance works were under way to consolidate it".
It went on to say that "a bridge-crane was installed to allow maintenance works to be carried out", adding that "the work and status of the viaduct were subject to constant observation and supervision" by their Genoa division.
"The causes for the collapse will be the subject of an in-depth analysis as soon as it is possible to safely access the site," the company said.
Genoa Mayor Marco Bucci told CNN the bridge collapse was "not absolutely unexpected".
"(It's a) very bad time with the collapsing of the bridge which was not absolutely unexpected. But we don't know the reason," he said.
"My role as the mayor is to make sure we have the correct infrastructure for the city and make sure that from the government we get the right amount of money in order to be able to set up the new infrastructure as soon as possible."
Transport Minister Danilo Toninelli said it was "unacceptable" and that "whoever made a mistake must pay", assuming negligence was the cause.
Mr Conte travelled to the site of the disaster this morning saying "it is shocking to see the twisted metal and the bridge collapsed with victims who were extracted".
He also praised the hundreds of rescue workers still at the site, saying "they saved people who fell 45m and are now alive and in the hospital".
Around 200m of the 45m-high bridge came crashing to the ground in large blocks — along with the cars and lorries travelling on it — in Genoa on Tuesday morning.
"We're not giving up hope. We've already saved a dozen people from under the rubble," said rescue official Emanuele Giffi.
"We're going to work round the clock until the last victim is secured."
The search for survivors continues among three areas where the debris fell.
"There are buildings that have been hit but it seems that all the victims were on the bridge," Mr Giffi said.
At least four people were pulled alive from cars in the rubble and were being transported by helicopter to a hospital.
Police K9 units were at the scene as rescue teams tried to locate survivors, as emergency services said dozens of cars were still trapped.
Firefighter Amalia Tedeschi said the bridge had mostly fallen on rail tracks below, taking "cars and trucks" with it.
Firefighters told the Associated Press that there are concerns about gas lines.
Earlier, Interior Minister Matteo Salvini said some 200 firefighters responded to the accident.
"We are following minute by minute the situation of the bridge collapse in Genoa," Mr Salvini said on Twitter.
He later reportedly said that spending on safety of Italians should come before budget constraints.
The disaster occurred on a highway that connects Italy to France and other holiday resorts on the eve of a major Italian holiday, Ferragosto.
Photos published by the ANSA news agency on its website showed a huge gulf between two sections of the highway.
Video captured the sound of a man screaming: "Oh god, oh god."
Other images showed a green truck that had stopped on the bridge just metres short of the gaping hole in the bridge.
The Morandi Bridge, designed by the engineer Riccardo Morandi, was built between 1963 and 1967 by the Italian Society for Water Pipelines.
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