Workers around the world held May Day rallies Monday to press for better factory conditions and higher wages in mostly peaceful marches, while activists in the Philippines and Belarus used the holiday to show their opposition to their governments in tense protests watched by police.

In Sri Lanka, where violence between Tamil Tiger rebels and the military has heightened fears of a return to civil war, the government canceled all May Day rallies in the capital, Colombo. Traditionally, almost all Sri Lankan political parties hold May Day rallies.

About 100,000 workers took to the streets across Indonesia, protesting a labor law that would cut severance packages and introduce more flexible contracts that would chip away at worker security.

"Don't change the law," thousands of laborers chanted in downtown Jakarta, as others arrived in buses and trucks, waving green, yellow and red flags and banners. Fearing violence, about 13,000 police were deployed, some carrying riot shields and manning water cannons, said police chief Maj. Gen. Firman Ganisaid. No incidents were reported.

Most rallies across Europe were peaceful, although tensions were evident in Belarus, where about 2,000 opposition supporters marched in the capital of Minsk in a show of defiance, days after the authoritarian government of President Alexander Lukashenko tried to stop an unprecedented series of demonstrations by throwing protest leaders in jail.

The Minsk rally began with an unauthorized march by 800 activists, who walked about 1 1/4 miles from the Academy of Sciences to a square where authorities had given permission for the gathering, which grew to about 2,000. Police officers stood on either side of opposition demonstrators as they made their way to the square, warning them that they were breaking the law, but did not intervene.

However, police later stopped opposition figure Stanislav Shushkevich, who had organized the march, and summoned him to appear in two days' time at a police station on charges of staging an unauthorized rally.

"Political repression is continuing. The authorities are acting more and more harshly and this means that they are afraid of us. I have no doubts that on May 3 that I will join the Belarusian leaders who are already in jail," Shushkevich, a former leader of Belarus in the 1990s before Lukashenko took power, told The Associated Press.

Hundreds of thousands of people turned out across Russia for more traditional May Day celebrations.

About 25,000 people gathered in Moscow opposite the mayor's office in the warm spring sunshine to hear speeches from trade union leaders and the mayor and listen to a concert, the ITAR-Tass news agency reported.

In Turkey, Istanbul police fired tear gas and pepper spray at demonstrators shouting slogans against the United States and the International Monetary Fund, and detained about 40 of them. In the town of Elazig in eastern Turkey, another 30 were detained following a scuffle with police that left four people injured.

In the Philippines, government troops and police armed with batons and shields turned away hundreds of activists who tried to approach the presidential palace to demand a wage increase and President Gloria Macapagal Arroyo's ouster.

Government troops and police, on the highest state of alert, had banned protests near the Malacanang palace in Manila for security reasons and amid rumors of a coup against Arroyo, who has been grappling with widespread calls for her resignation over allegations of vote-rigging and corruption.

After holding May Day rallies in nearby parks, about 7,000 left-wing laborers and followers of ousted President Joseph Estrada marched toward the historic Mendiola bridge near the palace, carrying a huge red streamer that read: "Down with Gloria!"

But they were blocked by riot police with truncheons and shields, according to police and TV footage. The two sides started pushing each other at one point.

After brief negotiations, police allowed the protesters to hold a rally until before nightfall at a busy junction where they were stopped, police Chief Inspector Edgar Alintog told the AP by telephone. The protesters later left without incident.

In Cambodia, thousands of police brought the capital of Phnom Penh to a virtual standstill during a government clampdown on an unauthorized May Day demonstration.

Opposition leader Sam Rainsy said one protest organizer was detained by police for two hours after hundreds of workers gathered on Russian Boulevard — a main road into the capital — seeking to march through the city.

The government had denied permission for the rally, allowing only one official May Day demonstration at Chenla theater, and police armed with riot shields and batons physically prevented protesters from marching.

"Cambodia still lacks real democracy, there is no real respect for human rights," Sam Rainsy said.

Thousands of garment factory workers rallied in Bangladesh to demand the United States and Europe drop tariffs on their products, saying they could eventually cause the industry's collapse. Others wound through the streets of the capital, Dhaka, banging drums and singing as they called for better working conditions in dangerous factories.

"No more death in factories," they chanted.

South Korean protesters demanded equal status and protection for all workers, and vowed to thwart a government plan to negotiate a free trade agreement with the United States. Critics say the pact will cost jobs.

In Bosnia, where the holiday is normally marked by picnics and celebration, the unemployed marched down Sarajevo's main street, demanding new elections and the resignation of the government, which they claim is not doing enough to lower the unemployment rate and bring Bosnia closer to the European Union.

The unemployment rate in the country has been above 40 percent for years. Bosnia is struggling with the destruction of its economy and infrastructure as well as the ethnic division that resulted from the 1992-95 war.

In the Austrian capital, Vienna, about 120,000 members of the opposition Social Democratic Party participated in a traditional May Day march, a show of party pride ahead of this autumn's parliamentary elections.

Thousands marched in central Athens to protest the war in Iraq and the Greek government's economic policies.

Aleida Guevara, the daughter of Latin American revolutionary icon Ernesto "Che" Guevara, was among 6,000 marching to the U.S. Embassy — a traditional target of many Athens' protests. The protesters cheered when they saw actor Tim Robbins, who opposes the war in Iraq and was in Athens to present a theatrical production.