Zurich police reported on Saturday evening that about 250 leftwing militants were detained in clashes on the sidelines of the official celebration. Many were later released after identity checks. Police used water cannons, rubber bullets and tear gas to disperse masked stone-throwing protesters.
About 120 masked demonstrators went on the rampage in Basel causing what the Swiss News Agency described as "enormous" damage.Trams were sprayed, shop windows broken and a Molotov cocktail thrown at a police station. There were about 15 arrests.