Messages posted on the internet and via text messages had called for another open-air illegal party in Zurich on Saturday, SF television reported. Police waited until the early morning hours but the streets of the city remained calm.
“Basel relieved Zurich as the scene of a riot night last weekend,“ according to Basler Zeitung (BAZ).
Early on Saturday evening, rumours spread that an illegal party was planned in Basel.
Basel police said on Saturday night and early Sunday morning they received many calls complaining about loud youths who had gathered in Voltaplatz, a square outside the city centre.
The rioters set a pile of building materials alight and when the fire brigade arrived at around 3am to put out the fire masked rioters smashed the windows of nearby shops and demolished a tram station.
The cost of the damage to property has not yet been assessed, but is thought to be extensive.
“It escalated suddenly from zero to a hundred,“ police spokesman Klaus Mannhart told BAZ. “I don’t know what was going on in their heads.“
Mannhart said he thought the fire was a tactic to deflect attention.
As soon as police reacted with rubber bullets and water cannons, the rioters ran in all directions. Two locals from the anarchist scene were arrested, police said.
Basel residents criticised the police for acting too late and not arresting more rioters, BAZ reported.
Police say they have been watching left-wing activists who have taken over an area of the local Voltamatte park, after several complaints were made by residents. The activists built a makeshift watchtower in May as a protest against the over-gentrification of the area.
Mannhart said that most of the rioters were from Basel.
“There is no evidence that the events have anything to do with those in Zurich,“ Mannhart said.
Justice and safety director Hanspeter Gass has called on the cantonal police to write up a detailed report on the events in Voltaplatz.
“Under no circumstances can it go on like this. Local residents are in my opinion right to be outraged,“ he said.