BRUSSELS (Reuters) - Tens of thousands of people marched through Brussels on Wednesday in a day of protests across Europe against government austerity measures, which unions say will slow economic recovery and punish the poor.

Up to 5,000 protesters also marched in Warsaw, Spanish unions staged a general strike and trade unions called protests in 11 other capitals to oppose measures such as spending cuts and pension and labor market reforms.

Unions said they achieved their goal of bringing 100,000 people onto the streets of Brussels, but police put the figure at 56,000 and said 218 people were detained for minor offences. Attendance at other rallies appeared to be much smaller.

“This is the start of the fight, not the end. That our voice be heard is our major demand today -- against austerity and for jobs and growth,” John Monks, head of the European Trade Union Confederation, told marchers at a rally near the European Union’s headquarters in Brussels.

Marchers from across Europe waved union flags and carried banners saying “No to austerity” and “Priority to jobs and growth,” bringing parts of central Brussels to a halt.

The protest was led by a group dressed in black suits with black face masks, carrying umbrellas and briefcases, representing financial speculators acting as the head of a funeral cortege mourning the death of Europe.

Marchers were angry that governments which spent vast sums rescuing banks now said ordinary citizens had to accept austerity.

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“The main feeling of the people is that for the banking system there are millions and billions of euros, but the social payments are being cut. That’s not right,” said Ralf Kutkowski, a German coal miner protesting in the Belgian capital.

European Commission President Jose Manuel Barroso told reporters the EU was aware of the “social knock-on effect” but governments saw the measures as the only way out of crisis.

Economists say the protests are unlikely to force governments to abandon structural reforms.

“I think at the moment they (the protests) are not that great a threat,” David Lea, western Europe analyst at Control Risks consultancy, told Reuters Insider television.

“And I think there’s an acknowledgement that a lot of these austerity measures are just going to happen and they’re not going be able to push governments off them.”

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LIMITED IMPACT OF SPANISH STRIKE

European governments say they have been forced into austerity to avert the danger of a sovereign debt crisis like the one suffered this year by Greece, but many workers feel they are being punished for problems that were not of their making.

“We understand there is a crisis, but it is being used as a very good excuse for all kinds of pressure on the people who are employees, workers and not in big business,” said Alexander Nikolov, who drove from Bulgaria to protest in Brussels.

Protests have taken place in many countries in the last few months. Rallies were called on Wednesday in Brussels, Dublin, Lisbon, Rome, Paris, Riga, Warsaw, Nicosia, Bucharest, Prague, Vilnius, Belgrade and Athens.

Spain’s first general strike for eight years, a protest against the Socialist government’s public spending cuts and easier hire-and-fire laws, had a limited effect beyond disrupting transport and some factories.

Spanish unions said 10 million people, or more than half the workforce, were on strike. The government said less than 10 percent of public administration workers and only 20 percent of Madrid transport workers were on strike.

Greece’s main unions planned an evening march to parliament to protest against austerity measures. Smaller unions called walkouts, hospital doctors stopped work for 24 hours and public transport was disrupted.

In Warsaw, protesters including miners and shipyard workers marched to Prime Minister Donald Tusk’s office chanting “No to budget cuts” and “Yes to job protection and economic growth.”

“It should not be only we workers, who produce the nation’s wealth, who bear the consequences of the economic crisis,” said Ireneusz Wisniewski, a trade union member from northeast Poland.

In Slovenia, about half of public sector workers were on strike for a third day against a planned wage freeze, causing jams at border crossings with Croatia. [ID:nLDE68Q0VD]

Economic growth has revived in the EU, home to 500 million people, and the bloc forecasts its economy will grow 1.8 percent this year after a 4.2 percent contraction in 2009.

But EU unemployment is running at 9.6 percent of the workforce, and at around twice that rate in Spain, Latvia and Estonia. Unions say austerity will curb job creation.

Financial markets are also worried about whether countries such as Ireland and Portugal can manage their debt burdens and tough sanctions are likely to be imposed on countries that break debt and budget deficit rules.