Violent clashes at an unauthorized anti-Israel rally in the Swiss capital of Bern this weekend left 18 law enforcement officers and two demonstrators injured, and caused extensive property damage, police said Sunday.

The demonstration in the city on Saturday afternoon drew more than 5,000 people, including a large number clad in black and wearing masks, who clashed with police and vandalized property.

The “demonstration escalated into unrest, causing significant property damage,” Bern police said in a statement.

“Law enforcement officers were also repeatedly attacked with dangerous objects,” including construction equipment, furniture, rocks, bottles, fire extinguishers, fireworks and laser pointers, it said.

Police responded “with force,” using water cannons, tear gas, rubber bullets and police batons, it added.

In all, 16 male and two female officers were injured, including four who had to be hospitalized, police said, adding that it was aware of two other people who required medical attention following the clashes.

The property damage was “extensive,” the statement said, describing smashed shop windows and ATM screens, tagged and defaced facades, and nine police vehicles “heavily damaged or tagged.”

More than 50 properties in Bern were damaged, with windows smashed and graffiti sprayed on buildings, police said.

The total amount of damage was expected to be “in the millions” of Swiss francs (1 franc = $1.25 USD), police said.

A total of 536 people were detained and had their identities checked before being removed from the area.

One of those checked was already the subject of an arrest warrant, the statement said, adding that others risked charges for offenses including rioting, property damage, home invasion, bodily harm, intentional arson, and violence or threats against authorities.

The rally was organized by various pro-Palestinian groups and left-wing organizations, including the Swiss Climate Strike and the Young Communists, according to the SWI news outlet, which noted that Amnesty International teams were also present to monitor the protest.