Tens of thousands of people have taken to the streets around the world to mark International Labour Day, including Turkey, Hong Kong, Russia and Indonesia.
In Istanbul on Thursday, police dispersed hundreds of protesters who tried to defy a ban on demonstrations in the city's Taksim Square on the anniversary of clashes that prompted a nationwide protest movement.
The square has been the scene of protests that have dogged the government for months.
After giving a final warning, hundreds of riot police backed up by water cannon moved in on protesters in the Besiktas district as they tried to breach the barricades leading up to the symbolic square, an AFP reporter said on Thursday.
Rallies also took place across Asia, including in Hong Kong, Jakarta, Kuala Lumpur, Singapore, Taipei and Seoul, where the annual protest was expected to take a sombre tone in the wake of the South Korean ferry disaster.
Russian workers, meanwhile, were to parade on Red Square for the first time since 1991 - the latest Soviet tradition to be revived as a wave of patriotism sweeps the country.
May Day was a key date in the Soviet calendar, with elaborate celebrations involving ranks of marching athletes, soldiers and workers on the Moscow square, but in recent years the annual demonstrations have been relegated to a city highway.
In Cambodia, security forces armed with sticks and batons forcibly dispersed dozens of May Day protesters near Phnom Penh's Freedom Park, according to an AFP photographer. Several people were beaten.
"We are sad that we could not mark May Day properly. Workers' rights have been thwarted," said Ath Thorn, president of the Coalition of Cambodian Apparel Workers Democratic Union.
Tens of thousands of Moroccans also demonstrated for higher minimum wages.
The government on Wednesday announced a 10 percent rise in the private sector monthly minimum wage from $287 and an increase in the public sector monthly minimum wage to $369, but the country's labour organisaitons issued a joint statement, saying the changes were not enough.
Indonesian police said about 33,000 workers were set to rally across the capital Jakarta.
Unions said up to two million workers would be out in force to demand better working conditions in Southeast Asia's most populous nation, although in previous years the numbers have come in much lower than such forecasts.
"Demonstrations will be held nationwide but the biggest will be in Jakarta, with around 33,000 workers," Rikwanto, police spokesman, told AFP, adding that 18,000 police officers would be out on the streets.
He said workers were planning further rallies on Friday.
In Hong Kong, union organisers said some 5,000 people were set to join their march from the city's Victoria Park to government headquarters, with better working hours top of the agenda.
In Seoul about 5,000 workers were expected to rally outside Seoul railway station in the afternoon but this year's traditional May Day trade union gathering has been overshadowed by the ferry disaster that has claimed the lives of hundreds of people, many of them schoolchildren.
The workers were to march to City Hall and pay their respects to the victims of the April 16 disaster at a temporary memorial.