It happened on the Giudecca Canal – a major thoroughfare that leads to Saint Mark’s Square – on Sunday morning at 8.30am.
Video of the crash shows the 80-metre cruise ship apparently unable to halt its momentum, blaring its horn as it ploughs into the much smaller river boat and the dock as dozens of people run away in panic.
“Some scared passengers dived into the water, while others fled the boat,” Venice resident Ida Ossi told local media.
Previous reports suggested that five people had been injured, but Venice port authorities later confirmed only four had been. They were taken to the hospital, but none of them sustained serious injuries. Their nationality is not known yet.
Davide Calderan, the president of the company that owned the two towboats steering the cruise ship before the accident, told Italian news agency ANSA that the cruise ship’s engine had a mechanical problem and was locked when the captain called for help.
“The two towboats were trying to stop the giant until one of the tow cables broke, cut in the collision with the river boat,” he said.
Local activists have campaigned for Venice to ban large cruise ships from entering the lagoon for years to protect its ecosystem and the incident has revived calls for the ban.
Activists were seen protesting on the scene of the accident.
“Today’s accident in Venice’s port demonstrates that large ships can no longer sail on the Giudecca canal,” Italy’s infrastructure minister Danilo Toninelli tweeted.
“After years of inactivity, we are finally close to a definitive solution to protect both lagoon and tourism.”
Venice mayor Luigi Brugnaro demanded the opening of alternative routes for cruise ships to reach the city in a Facebook post. “It’s no longer thinkable that large ships sail on the Giudecca Canal,” he wrote.
Venice attracts some 28 million visitors each year, or 76,000 per day.
Researchers of the Ca’ Foscari University of Venice have estimated that Venice should welcome no more than 19 million visitors a year for sustainable tourism, or 52,000 per day.