Police in Zurich have clashed with protesters during the city's rally to mark Labour Day.
In what has become an annual ritual, police armed with teargas and rubber bullets, and supported by water cannons, dispersed masked demonstrators toting Molotov cocktails on the sidelines of Zurich's main May Day rally.
Police said 100 people were arrested during clashes with 300 radical demonstrators that spilled into the city's red light district after the end of the rally. Altogether 10 protestors were injured, including one seriously, as well as four policemen.
The trouble started when several hundred protesters continued to demonstrate after the end of the official rally, and were then confronted by far-right activists, according to police. Protesters, some of them masked, threw stones and fireworks at officers.
The protesters had earlier tried to reach the offices of the U.S.-Swiss Chamber of Commerce but were unable to get through police barricades. The demonstration was unauthorized, police said.
The city's main rally attracted some 7,000 people - roughly the same as in past years - and passed off relatively peacefully.
Marches also took place in Geneva, Basel and Bern. As well as demanding better rights for workers, speakers condemned the fat pay packets handed out to top managers, and spoke out against the planned liberalisation of Switzerland's electricity market.
Speakers for the trade union federation used the day to applaud the unions' success in combating the wholesale privatisation of state-owned industries, saying they had seen off the worst attacks on the social welfare system and the public service.
They also cheered their recent success in securing an earlier retirement age for construction workers, describing it as an "historic breakthrough".
Strong words were directed at executives over their pay packets, reflecting the recent controversy over the salaries of bosses at the Swiss Federal Railways and the pension benefits for two former chiefs of the electrical engineering firm, ABB.
Addressing a rally in Fribourg, the interior minister Ruth Dreifuss, warned of the rise in rightwing extremism following the success of the far-right Jean-Marie Le Pen in the first round of the French presidential elections.
And Israel came in for strong criticism at many of the rallies for its heavy-handed policy in the occupied territories.
Similar protests were staged in cities across Europe. In France, anti-Le Pen rallies were held across the country, eclipsing a march by some 10,000 supporters of Le Pen's National Front party in Paris.
In Moscow the Russian president, Vladimir Putin, addressed a crowd estimated at 140,000 strong, overshadowing a nearby communist demonstration demanding the government's resignation.
swissinfo with agencies