Violent clashes marred trade union-led demonstration in the Belgian capital of Brussels today, where some 100,000 workers gathered to protest against the government’s free-market reforms and austerity measures.

For around two hours, the unexpectedly large crowd rallied peacefully in the main streets of central Brussels, against measures they claim are damaging the welfare state.

The trade unions object to government policies that promise to raise the pension age from 65 to 67, freeze the automatic link between wages and inflation, and cut public services in a way that would affect the entire population.

Violence later broke out, with police firing tear gas and using water canon against the crowd to break up incidents. No casualties were immediately reported.

Philippe Dubois, a protester who came from the industrial rust belt of Liege, told reporters:"They are not looking for money where it is, I mean people with a lot of money."

The event launched a month-long campaign by trade unions against the pro-business governing coalition, which will culminate in a nationwide strike on 15 December.

Brussels Protest - In Pictures Show all 10 1 /10 Brussels Protest - In Pictures Brussels Protest - In Pictures Brussels protest Protesters carry placards as they march through central Brussels REUTERS/Yves Herman Brussels Protest - In Pictures Brussels protest Thousands of people took part in the demonstration EPA/JULIEN WARNAND Brussels Protest - In Pictures Brussels protest A child sits on the shoulders of her father during the national trade union demonstration AP Photo/Geert Vanden Wijngaert Brussels Protest - In Pictures Brussels protest Demonstrators confront riot police in the centre of the capital REUTERS/Yves Herman Brussels Protest - In Pictures Brussels protest Workers stop cars on a main boulevard AP Photo/Geert Vanden Wijngaert Brussels Protest - In Pictures Brussels protest Demonstrators confront riot police REUTERS/Yves Herman Brussels Protest - In Pictures Brussels protest Policemen carry an arrested protestor AP Photo/Geert Vanden Wijngaert Brussels Protest - In Pictures Brussels protest Riot policemen charge during the protest AP Photo/Geert Vanden Wijngaert Brussels Protest - In Pictures Brussels protest Demonstrators confront riot police during clashes in central Brussels REUTERS/Francois Lenoir Brussels Protest - In Pictures Brussels protest A protestor wearing a gas mask throws a metal box into a burning car during a national trade union demonstration in Brussels AP Photo/Geert Vanden Wijngaert

Trade union leader Rudy De Leeuw vowed to continue the protests in the coming weeks, as government-led talks with employers and unions commenced on Thursday.

Belgium has a long postwar tradition of collective bargaining between employers and workers, and successive coalition governments representing a full scale of public opinion often have been able to contain social disagreements.

But the current coalition, made up of three pro-business parties and the centrist Christian Democrats, is the first in decades that has been able to set such a clear free-market agenda.

The government says it has been forced to push through stringent austerity measures to keep the budget deficit within European Union constraints and insists that businesses need more lenient tax policies to become more competitive in the global market.