Protesters in San Juan also called Wednesday for much faster federal help in the island's recovery from September 2017's Hurricane Maria. Many in the crowd waved Puerto Rican flags made in black and white rather than red, white and blue to symbolize mourning for the territory's plight.
Participants also urged the local government to save a public pension system that faces nearly $50 billion in payments it doesn't have funds to cover. A protester dressed as comic book superhero Spiderman was arrested after jumping over a street barrier and hugging a police officer.
Hundreds of thousands of Cubans have taken part in the country's annual May Day march, filing past former President Raúl Castro and successor Miguel Díaz-Canel in an event dedicated to denouncing new restrictions and sanctions announced by the U.S. government.
The crowd held an enormous white banner that read, "Unity, Commitment and Victory" in red letters.
The U.S. recently said it would place a new cap on the amount of money that families in the United States can send relatives in Cuba and moved to restrict "non-family travel."
Loudspeakers blared the words of a march leader: "No foreign or extra-territorial law will take decisions in our country."
Italian news agency ANSA says two protesters and a police officer were injured when police blocked a demonstration to oppose construction of a high-speed rail tunnel between France and Italy.
ANSA said none of the injuries on Wednesday were reported to be serious.
The group of protesters who assembled on a street in Turin included members of the 5-Star Movement, which opposes the tunnel through the Alps. Torino city councilor Damiano Carretto said on Facebook he was hit on the head and hand with a police truncheon.
The movement's partner in governing Italy, the League, has supporters that consider the tunnel vital. The 35.7-mile (57.5-kilometer) long Turin-Lyon High-Speed Train link is a key part of a European Union project linking southern Spain with eastern Europe.
A deputy with the Democratic Party has accused the rival 5-Stars of pushing and verbally abusing Democrats at May Day celebrations.
French police and some violent protesters have clashed again during a May Day march in Paris.
Some of the troublemakers, wearing masks and black hoods, could be seen throwing rocks and other objects at riot police, who responded with tear gas and flash grenades near the Place d'Italie square.
More than 7,400 police officers were deployed on Wednesday for May Day events in Paris. More than 200 people had been arrested by mid-afternoon.
Authorities had warned against the presence of "radicalized protesters."
The masked protesters clashed with police earlier at the starting point of the main march, near Montparnasse train station.
Activists with France's yellow vest movement joined the traditional march to show solidarity with labor unions in rejecting French President Emmanuel Macron's economic policies.
An activist group says more than 100 people have been arrested at May Day rallies across Russia, with over half of the detentions taking place in St. Petersburg.
The OVD-Info group said Wednesday that at least 68 people were detained in St. Petersburg, Russia's second-largest city, in an anti-government contingent that authorities had sanctioned as part of the main May Day demonstration. Two people reported injuries.
Police brutally manhandled people in the opposition contingent, including local lawmaker Maxim Reznik. He was released quickly because of his status as a public official.
Reznik told the Dozhd TV station that officers detained almost everyone in his protest group and would not give the reason for the arrests.
Some of them were carrying placards saying "Putin is not immortal" in reference to President Vladimir Putin who has been at the helm of the country since 2000. Most of them are supporters of opposition leader Alexei Navalny.
Police have briefly clashed with protesters in Goteborg, Sweden's second-largest city, and in Copenhagen, the capital of Denmark, as May Day rallies were being held.
In Sweden, protesters threw cobblestones and fireworks at police as they were being kept away from reaching a rally by a neo-Nazi movement that had received official permission to march.
In Copenhagen, helmeted police circled their vans around a group of hooded people in black who were shouting anti-police slogans, trying to keep them away from other May Day demonstrations.
A handful of people were detained in both countries.
The heaviest May Day clashes in Europe took place in France, where police clashed with stone-throwing protesters as tens of thousands of people started marching in Paris on Wednesday under tight security. More than 200 arrests were made.
Car-sharing companies are urging customers in Berlin not to park vehicles in areas where May Day protests are expected.
Miles, which has a fleet of cars in the German capital that can be reserved with an app, warned customers against leaving them in parts of the Kreuzberg and Friedrichshain district s until Thursday.
Rallies and May Day celebrations are planned in both areas and have in the past erupted into violence, with protesters torching vehicles.
French protesters and police have clashed briefly in Paris as thousands of people gather for a May Day march.
Authorities fear some troublemakers could join anti-government protesters and union workers.
Police used some tear gas to control a crowd near Paris' Montparnasse train station.
AP reporters observed groups of hooded people in black shouting anti-police slogans, mixing with other protesters wearing yellow vests or waving union flags.
French authorities warned "radical activists" may join the Paris demonstration and renew scenes of violence that marked previous yellow vest protests and May Day demonstrations in the past two years.
More than 7,400 police have been deployed in Paris.
Yellow vests have joined traditional May Day union march to show their common rejection of French President Emmanuel Macron's economic policies.
Spain's workers are marching on May Day in major cities to make their voices heard days before acting Prime Minister Pedro Sánchez starts negotiating with other parties to form a new government.
Spain's leading labor unions are pressing for Sánchez to roll back business-friendly labor and fiscal reforms that have remained in place since the previous conservative administration.
Sánchez's Socialist party won Sunday's election on Sunday, but will still need other parties to form a government and pass laws. Sánchez will meet with the leaders of the three other top vote-getters next week. The far-left United We Can party is offering to enter the new Socialist government.
Unai Sordo, leader of Spain's CCOO union, says in Madrid that "the result of the general elections gives us the possibility for a progressive political majority."
Activists say more than a dozen people have been detained in Russia's second-largest city for participating in an unsanctioned political protest on May Day.
The OVD-Info group that monitors detentions of political activists says that at least 15 people were detained at the May Day rally in St. Petersburg. Most of them are supporters of opposition leader Alexei Navalny.
The activists were marching with the main May Day demonstration through central St. Petersburg. Some of them were carrying placards saying "Putin is not immortal" in reference to President Vladimir Putin who has been at the helm of the country since 2000.
An opposition party in South Africa is using May Day to rally voters a week before the country's national election.
Economic Freedom Fighters members, wearing their signature red shirts and berets, gathered at a stadium in Johannesburg to cheer in support of populist stances that have put pressure on the ruling African National Congress to address issues like economic inequality and land reform.
The EFF has made some South Africans uncomfortable, however, with comments about foreigners and whites.
Greece has been left without national rail, island ferry and other transport services for a day as unions hold strikes and rallies to celebrate May Day.
Hundreds of people gathered in central Athens Wednesday for three separate rallies and marches to parliament organized by rival unions and left-wing groups.
The Greek capital was left without public bus, trolley bus and urban rail services all day due to a 24-hour transport union strike, although the city's metro trains were running most of the day.
The national train and island ferry services are set to resume Thursday.
Russian authorities say that about 100,000 people are taking part in a May Day rally in central Moscow.
Moscow police said on Wednesday that the rally organized by Kremlin-friendly trade unions on Red Square attracted around 100,000 people.
Over the years, the May Day in Russia has transformed from the occasion for rallies for workers' rights to an official event carefully orchestrated by Kremlin-controlled groups.
Opposition activists, however, often try to use the May Day to promote their agenda.
The respected activists' group OVD-Info which compiles police reports on detentions of political activists said that six political activists have been detained in Moscow before the morning rallies. Separately, in the remote Petropavlovsk-Kamchatsky in Russia's Far East, police have detained at least 10 people who showed up at the local May Day rally wearing yellow vests in an apparent nod to the protest movement in France.
Turkish police detained May Day demonstrators who tried to march toward Istanbul's symbolic main square in defiance of a ban.
Turkey declared Taksim Square off-limits to May Day celebrations citing security concerns. Roads leading to the square were blocked Wednesday and police allowed only small groups of labor union representatives to lay wreaths at a monument.
Still, small groups chanting "May Day is Taksim and it cannot be banned," attempted to break the blockade. The official Anadolu news agency said more than two dozen were detained.
Trade unions and political parties will mark the day with rallies at government-designated areas in Istanbul and the capital, Ankara.
Taksim holds symbolic value for Turkey's labor movement. In 1977, 34 people were killed there during a May Day event when shots were fired into the crowd from a nearby building.
Ahead of a May Day rally in over a dozen German cities, Germany's biggest trade unions are urging voters to participate in this month's European elections and reject nationalism and right-wing populism.
The DGB, a confederation of unions with almost 6 million members, said Wednesday that the European Union has helped ensure peace on the continent for decades and brought significant benefits to millions, from paid holidays to maternity protection.
The unions called for ambitious EU-wide investments to boost employment and growth, saying "people must feel that the EU improves their lives in a lasting and tangible way."
The unions warned that the political and economic turmoil in Britain following its vote to leave the European Union nationalism "shows what happens if those who stoke fear but have no plan for the future gain the upper hand."
Thousands of trade union members and activists are marking May Day by marching through Asia's capitals and demanding better working conditions and expanding labor rights.
A South Korean major umbrella trade union has issued a joint statement with a North Korean workers' organization calling for the Koreas to push ahead with engagement commitments made during a series of inter-Korean summits last year.
Many of the plans agreed between the Koreas, including joint economic projects, have been held back by a lack of progress in nuclear negotiations between Washington and Pyongyang.
May Day rallies are also being held in the Philippines, Malaysia, Cambodia, Myanmar and elsewhere in Asia.