THE HAGUE, Netherlands — Dozens of people armed with sticks and firecrackers set fire to a tram in Amsterdam on Monday, police said, as the city grapples with tensions following last week’s violence. targeting fans of an Israeli football club.

Police said the fire was quickly extinguished and riot officers cleared the square. Images online showed people destroying property and setting off firecrackers.

Police said it was unclear who started the unrest and whether it was related to what happened last week. But they noted the tense atmosphere as five people were treated in hospital and dozens were detained following a Maccabi Tel Aviv-Ajax match on Thursday. Youths on scooters and on foot went in search of Israeli fans, punching and kicking them and then running to evade police, according to Amsterdam’s mayor.

Dutch police on Monday announced five new arrests in the investigation into earlier violence. The suspects are men between the ages of 18 and 37 and are from Amsterdam or surrounding cities. Four are still in custody; the fifth was released but remains a suspect.

Earlier, police said four other men who were arrested last week will remain in custody while the investigation continues. Two of them are minors, a 16-year-old and a 17-year-old from Amsterdam. The other two men are from Amsterdam and a nearby town.

Police said they identified more than 170 witnesses and took forensic evidence from dozens. Prime Minister Dick Schoof said he was also looking into videos posted on social media.

Reports of anti-Semitic speech, vandalism and violence have increased in Europe since the start of the Gaza war and tensions have risen in Amsterdam ahead of Thursday night’s match.

Local authorities banned pro-Palestinian demonstrators from gathering outside the stadium. Before the match, Maccabi fans also tore down a Palestinian flag from a building in Amsterdam and chanted anti-Arab slogans on their way to the stadium. There were also reports of Maccabi fans starting fights.

The mayor banned all demonstrations in the city and declared several parts of Amsterdam risk zones where the police can stop and control anyone. d dozens were detained on Sunday for attending a pro-Palestinian demonstration in central Amsterdam that had been banned.

Israel’s Foreign Minister Gideon Saar rushed to the Netherlands on Friday and offered Israel’s help in the police investigation. He met with the Dutch prime minister on Saturday and said in a statement that the attacks and demands to show passports “recall dark periods in history”.