Protests in Rotterdam against new Dutch Covid-19 restrictions turned violent Friday night, and police said they arrested 51 people, fired warning shots and used water cannons to control rioters who pelted officers with rocks, burned cars and set off powerful fireworks

The city-center riot followed new government restrictions to combat rising infections and hospitalizations. Violent protests against restrictions also occurred across the Netherlands in January.

Dutch...

Protests in Rotterdam against new Dutch Covid-19 restrictions turned violent Friday night, and police said they arrested 51 people, fired warning shots and used water cannons to control rioters who pelted officers with rocks, burned cars and set off powerful fireworks

The city-center riot followed new government restrictions to combat rising infections and hospitalizations. Violent protests against restrictions also occurred across the Netherlands in January.

Hundreds of people gather in Rotterdam during a protest Friday against new Covid-19 rules as infections and hospitalizations climb.

Photo: killian lindenburg/Shutterstock

Dutch police said Saturday that order had been restored around midnight following much damage. They added more arrests were likely after police from around the country were dispatched to the port city.

Seven people were injured, two of whom hit by bullets and remained hospitalized, police said. The National Criminal Investigation Department is investigating whether the bullet wounds were from rounds fired by police, as is routine in the Netherlands, Dutch police said on Twitter. Police officers were also injured, they said.

The riot began amid a peaceful gathering of roughly 100 protesters. “The atmosphere quickly became grim,” the police said on a live blog. Rioters threw stones at police and set off powerful fireworks, prompting police to lock down the area and close the city’s central train station, the police said.

Police used water cannons and fired warning shots to control rioters when the violence grew dangerous, the police said. About half of the 51 people arrested were underage, police said, and came from across the country.

A burned out car is among the debris on Saturday in the wake of a demonstration that turned violent in Rotterdam.

Photo: Ddp/Zuma Press

Write to Daniel Michaels at daniel.michaels@wsj.com