By Luke Baker and Stephen Adler
BRUSSELS (Reuters) - European Commission President Jose Manuel Barroso has warned against nationalism, xenophobia and racism ahead of European Parliament elections next year, when anti-EU and protest parties are expected to do well.
Opinion polls months ahead of the vote, which takes place in all EU countries on May 22-25, suggest candidates on the far left and far right will gain support as voters express frustration with Europe after three years of financial turmoil, contracting growth and job losses.
"We have to be honest that the crisis and the rise in unemployment is an occasion for populist forces to become more aggressive and gain some votes," Barroso, a former center-right prime minister in Portugal, told Reuters in an interview.
"What we don't like is the discourse that is sometimes behind anti-European slogans, a discourse that is promoting what I call negative values, things like narrow nationalism, protectionism and xenophobia. That is a concern.
"We should not forget that in Europe, not so many decades ago, we had very, very worrying developments of xenophobia and racism and intolerance. So I think everybody that has European principles should be worried about some of these movements."
Barroso did not mention any parties or movements by name. But polls suggest right-wing parties with strong positions on immigration could do well in several countries, including Britain, France and Finland.
In Britain, the UK Independence Party is predicted to come first or second in the elections, although a lot can change with seven months still to go before the vote.
In France, Marine Le Pen's far-right National Front has pulled away from the two mainstream parties and according to one recent poll is expected to win the election.
Besides the right-wing forces, there are far-left or protest movements in Greece and Italy that have strong popular backing, as well as single-issue parties such as Germany's anti-euro AfD that are expected to secure representation in the 760-seat European Parliament, the EU's only directly elected body.
Mainstream politicians and political analysts say it is too early to predict with any precision how many seats the anti-EU and protest parties will pick up, but broad estimates suggest it could be anywhere from 20 to 30 percent of the vote.
While they would be unlikely to act as a block in parliament, since they come from opposite sides of the spectrum and often have narrow, national-based issues on their agenda, some form of coordination among the larger far-right parties could end up disrupting decisions in parliament.
At the same time, Barroso said he was confident the mainstream political parties would remain largely dominant in the new parliament, and urged them to speak out for European values if they were to keep extremists in check.
"The pro-European forces...need to take the lead, not give the initiative to extremist forces, and explain in a rational and reasonable way what Europe brings," he said.
"That is why we are asking the so-called mainstream parties to have the courage to get out of their comfort zone, to think that today, at a time of crisis, we cannot take the European Union for granted."
(Writing by Luke Baker; editing by Ralph Boulton)