PARIS - The annual May Day demonstrations took on special resonance across Europe on Tuesday as tens of thousands of protesters turned out amid rising anger over enforced austerity that many see not as a cure to the region’s fiscal troubles, but as a deterrent to economic growth and job creation.

In Spain, trade unions estimated that more than 1 million people had taken part in protests across 80 cities, with the largest gatherings in Madrid and Barcelona. While organizers said 100,000 protesters had shown up in Barcelona, the police offered a starkly lower estimate of 15,000.

Spain has slipped into a recession for the second time in three years, joining 11 other European countries officially in recession. Labor unions have warned of mounting unrest if the center-right government of Prime Minister Mariano Rajoy pushes ahead with austerity measures to meet its budget-deficit targets while 5.6 million people - almost a quarter of Spain’s workforce - are unemployed.

“This is a May Day against the destruction of jobs and in favor of following other alternatives,’’ Candido Mendez, the leader of the UGT, one of Spain’s two main labor unions, said on Spanish television. The latest spending cuts, he warned, will amount to “the demolition of public services in our country.’’

Public outrage over the growing gap between rich and poor, and the struggle by average families to make ends meet, was also felt in Britain, France, Greece, and well beyond Europe into Asia. In Indonesia, the Philippines, and East Timor, demonstrators called for higher wages and better working conditions.

In London, members of the Occupy movement, who were evicted from a camp outside St. Paul’s Cathedral in February, released flying tents, lifted into the air by helium balloons, at the Liverpool Street railway station, while union leaders addressed a larger rally in Trafalgar Square.

In Germany, which has economically outperformed its neighbors, Chancellor Angela Merkel continued to insist that a tough diet of austerity measures was necessary to restore European economic competitiveness and to save the euro.

Yet a rising chorus of critics and government leaders, motivated by crushing economic realities and angry voters, has begun insisting that what is needed is growth, not more cuts. That was a message that May Day activists seemed to share regardless of nationality.

Even in Germany, where unemployment is at post-unification lows, hundreds of thousands of workers took to the streets. The German Federation of Trade Unions said more than 400,000 members had turned out for protests and marches. Michael Sommer, chief of the federation, criticized the austerity measures across Europe as dangerous and called for more growth.

In France and Greece, pending elections heightened the tensions of the day. President Nicolas Sarkozy of France rallied supporters for last-minute campaigning before the presidential runoff election, set for Sunday. He tried to turn the tables on the May Day protesters, calling his rally, which took place on one of three official weekday public holidays this month, a “celebration of work.’’

His Socialist challenger, Francois Hollande, at a rally in the city of Nevers, denounced what he deemed Sarkozy’s effort to capitalize on fears over the economy.

In Athens, where parliamentary elections are set for Sunday, a rally organized by Greece’s two main labor unions drew around 2,000 people, with 3,000 left-wing demonstrators staging their own rally. Both events were followed by scuffles between the police and stone-throwing youths.