Workers across the European Union are staging a series of protests and strikes against rising unemployment and austerity measures.
General strikes in Spain and Portugal halted transport, businesses and schools and led to clashes between police and protesters in Madrid.
Smaller strikes were reported in Greece, Italy and Belgium, and rallies were planned in other countries.
Hundreds of flights have been cancelled in Spain and Portugal.
Airlines are recommending passengers check the schedules before setting out to airports. The European Trade Union Confederation has co-ordinated the Europe-wide action.
The confederation’s Judith Kirton-Darling said that austerity was not working. “It’s increasing inequalities, it’s increasing the social instability in society and it’s not resolving the economic crisis,” she said. Some 40 groups from 23 countries are involved in Wednesday’s demonstrations. ‘There is just no work’
Unions in Spain and Portugal started strikes at midnight to protest against austerity measures that have combined tax rises with cuts in salaries, pensions, benefits and social services.
Marchers came out late on Tuesday in Spain, where 25% are unemployed, the highest rate in Europe. “I have two sons in my house, one is getting subsidies, the other has been at home for the last three years,” said protesting housewife, Paqui Olmo. “It is not that he doesn’t want to work, there is just no work.”
In the first reported clashes of the day, picketers and police fought at a Madrid bus depot where demonstrators were trying to stop buses from leaving.
There were outbreaks of violence in other Spanish cities, and the interior ministry said more than 30 arrests had been made. The government has played down the strike, saying the electricity grid is registering 80% of its normal usage. But unions claim the operations of several large companies, including Danone and Heineken, have ground to a halt.
In neighbouring Portugal, demonstrators took to the streets in the early hours, carrying banners denouncing the European Union, International Monetary Fund and European Central Bank.
The so-called troika has bailed out Portugal to the tune of 78bn euros ($100bn; £62bn), and demanded deep austerity measures in return.