Trade unions and other groups are staging rallies around the world to mark International Workers Day. A look at some May Day events:
Fearing France's worker protections are under threat, hundreds of angry youths on the sidelines of a May Day labor rally hurled stones and wood at police in Paris, receiving repeated bursts of tear gas in response.
Trade unions, teenagers, pensioners and families held largely peaceful marches Sunday in Paris and cities around the country. The traditional May Day rallies took on greater weight this year as parliament is debating a bill that would allow longer working hours and let companies lay workers off more easily.
The bill has prompted the most violent labor-related protests in a decade, with marches and sit-ins frequently degenerating into clashes with police.
Police encircled a few hundred suspected troublemakers on the sidelines of the Paris march Sunday, and frustrated youth threw projectiles. In Marseille, at least five people were arrested after scuffles with riot police. Marchers held banners calling President Francois Hollande a "traitor" and chanted "Everyone together!"
The Socialist government hopes the relatively modest labor reform will reduce chronically high unemployment and make France more globally competitive, by allowing companies more flexibility. Opponents say it erodes hard-fought worker protections and call it a gift to corporate interests.
Thousands of Turkish demonstrators rallied for May Day in an authorized area of Istanbul while police cracked down on other protests.
Police used tear gas and water cannons on demonstrators trying to reach Taksim Square. One man died after being hit by a water cannon vehicle.
Taksim has symbolic meaning as the center of protests in which 34 people were killed on May Day in 1977.
The office of the governor of Istanbul said 24,500 security officers reported for duty Sunday, and that 207 people were detained.
Tensions are running high in Turkey after a string of deadly suicide bombings linked to either Kurdish or Islamic State group militants.
In the capital, Ankara, police rounded up four suspected IS members who were allegedly planning to attack May Day demonstrators.
May Day marches were held elsewhere in Turkey without incident but were cancelled in the southern city of Gaziantep after a deadly car bombing on a police station.
In the coastal city of Izmir, some demonstrators stripped down in protest over police body searches at a square where people were allowed to gather, according to local media.
Tens of thousands of people marched across Moscow's Red Square on a sunny Sunday morning in a pro-Kremlin workers' rally. The protesters were carrying the Russian tricolor and balloons.
As is typical for rallies organized by the ruling United Russia party, the May Day rally steered clear of criticizing President Vladimir Putin or his government for falling living standards. The slogans focused on wages and jobs for young professionals.
Left-wing Russian groups held their own rallies.
This year the May Day coincided with the Orthodox Easter in Russia. Communist leader Gennady Zyuganov told Russian news agencies ahead of the rally that he celebrates Easter despite the Communist party's history of oppressing the Russian Church. When a supporter greeted him with "Christ has risen!" Mr. Zyuganov echoed "He is risen indeed!" in a traditional Orthodox greeting.
In Manila, about 2,000 left-wing protesters scuffled with riot policemen, who used shields and a water cannon to try to prevent the flag-waving demonstrators from getting near the U.S. Embassy. Labor leaders said 20 protesters were injured.
Some of the protesters managed to break through the police cordon. TV video showed some of them punching a retreating police officer and using wooden poles to hit a fire truck.
Police made no arrests and the protesters dispersed after about two hours.
May Day rallies were held across the Philippines, with campaigning entering the final week ahead of the May 9 presidential election. Some of the candidates pledged to address labor complaints.
"We'll see the real color and what will become to the sweet promises when one of them sits as president," left-wing labor leader Elmer Labog said.
Labour Party leader Jeremy Corbyn joined thousands of people at a May Day rally in central London, using the occasion to condemn the progress of far-right groups throughout Europe.
Standing atop a red London bus, Corbyn said the party is united against the far-right and against racism.
"We stand in solidarity now against the growth of the far right in Europe," said Mr. Corbyn, whose faltering opposition party has been accused of anti-Semitism in recent days.
Corbyn, who represents Labour's left wing, was the first Labour leader to address a May Day crowd in decades.
In Taipei, Taiwan's capital, labor unions took to the streets with a march to call on the government to reduce working hours and increase wages.
Many among the Taiwanese public have been concerned that outgoing President Ma Ying-jeou's push for closer economic ties with China has benefited just a few. Young Taiwanese have seen wages stagnate and good full-time jobs harder to find as the export-led economy has slowed.
Chen Li-jen, a protester with the Taiwan Petroleum Workers Union, said that while companies were seeing their earnings per share grow every year, workers' salaries were not rising in tandem.
"Hardworking laborers are being exploited by consortiums," Mr. Chen said.
"For the past decade, our basic salary has not made any progress," he said. "Laborers' rights have always been neglected. This is why I hope to take advantage of the May 1 Labor Day protest and tell the government that we are determined to fight for our rights."
Embattled Brazilian President Dilma Rousseff used a May Day appearance in Sao Paulo to rally support against efforts to impeach her.
The president announced to tens of thousands of backers that she will beef up a flagship social program, reduce the impact of income tax on the middle class and build another 25,000 new low-price homes.
A key vote on her impeachment proceedings is scheduled within two weeks in the Senate.
Meanwhile, at an anti-Rousseff rally, union leader Paulinho da Forca called the president's announcements "desperate measures."