Russia celebrated May Day with its first joyful parade across Red Square since the Soviet Union collapsed in 1991, as President Vladimir Putin basked in a surge of patriotism over Crimea's annexation. In Turkey, scores were injured in clashes with police.
Elsewhere in the world, demonstrators turned out Thursday to press their demands for better treatment on the holiday also known as International Workers' Day. A rally also turned violent in Cambodia's capital.
Security forces in Istanbul's iconic Taksim Square pushed back demonstrators with water cannons and tear gas. Protesters retaliated by throwing objects at police and using slingshots. Police said 142 people were detained and 90 were injured, 19 of them police officers.
Last week, city administrators said the square would be off limits to International Workers' Day demonstrations and most points of entry were blocked. Taksim is symbolic for Turkey's labor movement. In 1977, 34 people were killed in the square during a May Day event when shots were fired into the crowd from a nearby building.
The Moscow parade of about 100,000 people was organized by trade unions and ostensibly dedicated to honoring the working class. The overarching theme, however, was Russian pride over last month's annexation of Crimea. Putin, who did not attend, was saluted as a national hero.
A long stream of marchers held up signs saying "I'm proud of my country," ''Let's go to Crimea for vacation" and "Putin is right." Russian flags fluttered through the crowd.
In Soviet times, members of the ruling Politburo used to review the parade from atop the mausoleum where the body of the first Soviet leader, Vladimir Lenin, still lies.
Putin further tapped into nostalgia for the Soviet Union by handing out "Hero of Labor" awards during a Kremlin ceremony after the march. The awards, which were created under dictator Josef Stalin and disappeared along with the Soviet Union, were reinstated last year.
In past years, it has fallen to the Communist Party to keep up the May Day tradition. They held a separate rally Thursday in central Moscow that drew about 10,000 people.
May Day also is celebrated with huge organized marches in Cuba, where thousands filed through Havana's Revolution Plaza on Thursday to a soundtrack of congas, drums and cries of "Long live the revolution!"
Doctors in white smocks, uniformed government employees and construction workers waved Cuban flags and banners honoring Fidel and Raul Castro, guerrilla leader Ernesto "Che" Guevara and late Venezuelan President Hugo Chavez.
In Greece, more than 15,000 people attended peaceful rallies in central Athens to protest austerity measures in the crisis-hit country. Greece's largest trade union, GSEE, said the measures imposed in return for a bailout four years ago had "destroyed 100 years of effort" to establish labor rights. The union has organized 37 general strikes since the introduction of the austerity measures, which have severely cut incomes and benefits.
In Cambodia, civilian auxiliary police armed with clubs turned on demonstrators after opposition leaders spoke to a crowd of nearly 1,000 in Phnom Penh. The assaults appeared to be random and limited, and were over in less than an hour. At least five people were hurt, said Om Sam Ath of the human rights group Licadho.
A ban on demonstrations in Cambodia has been in place since January, following numerous labor protests for a higher minimum wage and opposition rallies denouncing last July's election as rigged.
Thousands of workers in Bangladesh, including many from garment factories, took to the streets demanding the execution of the owner of a building that collapsed last year, killing more than 1,100 garment workers.
Swedish police arrested about 20 people as counter-demonstrators tried to interrupt a march by neo-Nazis in the southern city of Jonkoping. Police said the two sides clashed briefly, but no serious injuries were reported.
In Paris, several thousand people gathered at Bastille square despite heavy rain. Demonstrators chanted anti-austerity slogans criticizing President Francois Hollande.
Labor unions held marches across Germany demanding higher wages and better working hours. Protests were mainly peaceful, but two people were injured in clashes between right- and left-wing activists in Duisburg, the German news agency dpa reported.
Hundreds of workers in Hong Kong joined a Labor Day march, calling for improved working conditions and for the government to restrict the number of working hours.
In the Philippines, thousands of workers marched peacefully in Manila to protest low wages and the practice of replacing regular employees with temporary hires who get low pay and little or no benefits. They also decried what they said was President Benigno Aquino III's failure to deliver on corruption reforms.
Thousands of Malaysians held a peaceful protest in downtown Kuala Lumpur against a looming goods and services tax they fear will increase the cost of living.
Iranian President Hassan Rouhani told thousands of laborers gathered in the capital, Tehran, that he supports the establishment of unions "free of any interference by the state." His predecessor, Mahmoud Ahmadinejad, had dissolved many unions, leaving only a few perfunctory and powerless organizations.
Dozens of people, mostly members of the Iraqi Communist Party, held a rally in downtown Baghdad, raising Iraqi flags and those of the former Soviet Union.
Associated Press writers from around the world contributed to this report.
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