A giant demon in the role of Philippine President Rodrigo Duterte was burned by protesters near the presidential palace in a lively Labor Day rally.
Thousands of workers marched in Manila to voice anger over what they said was the president's failure to scrap short-term employment contracts.
Police said some 5,500 people attended the marches and that the events were "generally peaceful".
Key protest areas were closed off in Istanbul, with the annual workers' holiday often the occasion for confrontation between demonstrators and police in Turkey.
Protesters who sought to defy the ban in central Taksim Square were taken away by police, supported by helicopters, armored cars and water canon vehicles.
Police said they arrested 84 people in Istanbul.
Thousands of people took part in officially-sanctioned May 1 events in the Istanbul district of Maltepe, and in other cities, at a time when political tensions are running high ahead of snap parliamentary and presidential elections in June.
In Havana, the first May Day march of the post-Castro era drew a colorful crowd of close to a million people.
Cubans carried posters of the Castro brothers and fellow revolutionary Che Guevara and unfurled huge copies of the country's flag, while children dressed as soldiers bounced on their parents shoulders.
The annual Workers' Day march at the capital's Revolution Square was the first major appearance for new president Miguel Diaz-Canel, who was accompanied by his predecessor Raul Castro.
Riot police were deployed to control crowds in Medillin, Colombia, where protesters threw stones at officers during clashes.
In Berlin, police officers looked on as demonstrators dressed in black from the "Revolutionary 1st of May Demonstration" lit flares. According to unions, some 500 events were planned nationwide, with many held under the slogan of "solidarity, diversity and justice".
But in Athens demonstrators carried red carnations in union marches through the Greek capital. One of the largest demonstrations of the Greek Communist Labour Union attracted at least 11,000 people.
Supporters of Brazil's former president Luiz Inacio Lula da Silva, who is serving a 12-year sentence for corruption, gathered in front of the Federal Police headquarters in Curitiba where he is being held. Wearing red, the color of the Workers' Party, and holding aloft signs calling for his release, they marked May Day by staging a "Good Morning Lula" event. – Rappler.com