The police in Amsterdam arrested five more people on assault charges this weekend, four of whom are still being held, over the attacks on Israeli soccer fans in the city late last week after a match between an Israeli and a Dutch team.

The total number of people who are still being held in connection to with the violence is now eight, the police said, and more arrests were possible. The people arrested were all men ranging in age from 18 to 37. The police urged people to share any video footage as a way to aid their investigation.

On Monday afternoon, Dick Schoof, the prime minister of the Netherlands, told Dutch reporters that the perpetrators who attacked Maccabi Tel Aviv supporters in Amsterdam primarily had “a migration background.”

“We have an integration problem,” Mr. Schoof said, “This is an expression of that.”

Over the past year, tensions related to the war in Gaza have been high in Amsterdam, a city with a large Muslim population angered by Israel’s conduct in the conflict, which was set off by the Oct. 7, 2023, Hamas-led attack on Israel. While most of the hundreds of Gaza-related protests in Amsterdam have been peaceful, some have turned turbulent. One disrupted the opening ceremony for the city’s new Holocaust museum.

On Monday night, the unrest continued, with riot police responding to vandalism and people throwing fireworks, which set a tram on fire in a square in the western part of the city. The police urged people to stay away from the square.

In neighboring Belgium, two boys — ages 14 and 17 — were arrested in Antwerp on Sunday and Monday, Antwerp officials said, for allegedly spreading calls on social media to attack Jewish residents in the city.