Galvanized by Arizona's tough new law against illegal immigrants, tens of thousands of marchers took to the streets in Los Angeles on Saturday as the city led the nation in May Day turnout to press for federal immigration reform.

Milagros Vizcaino, 13, of Los Angeles heads home after participating in the May Day march protesting Arizona's harsh new immigration law. (Brian van der Brug, Los Angeles Times)

As many as 60,000 immigrants and their supporters joined a peaceful but boisterous march through downtown Los Angeles to City Hall, waving American flags, tooting horns and holding signs that blasted the Arizona law. The legislation, which is set to take effect in midsummer, makes it a crime to be in Arizona without legal status and requires police to check for immigration papers.

Though the crowd was roughly half as large as police had projected, it was the largest May Day turnout since 2006, when anger over federal legislation that would have criminalized illegal immigrants and those who aid them brought out more than 1 million protesters nationwide. Since then, most activists have deemphasized street actions in favor of change at the ballot box through promoting citizenship and voter registration.

But this year is different. Outrage over the Arizona law, continued deportations and frustration over congressional delay in passing federal immigration reform prompted activists nationwide to urge massive street protests on this traditional day of celebrating workers' rights.

That call was heeded by marchers like Yobani Velasquez, a 32-year-old Guatemala native and U.S. legal resident. He said the Arizona law energized him to come out and join the Los Angeles march.

"It's a racist and unfair law," said the Sun Valley truck driver. "It hurts parents and children."

Rallies in more than 90 other cities drew thousands of people from New York to Phoenix. In Washington, D.C., thousands cheered as 35 immigration rights advocates, including U.S. Rep. Luis Gutierrez (D-Ill.), were arrested in front of the White House after they disobeyed police orders by sitting on the sidewalk along Pennsylvania Avenue, calling on President Obama to move immigration reform forward.

But the national epicenter for opposition to the Arizona law has become Los Angeles. City officials have called for a boycott of the state, Cardinal Roger M. Mahony has likened the law to Nazism, and activists put aside past differences to stage a unified march. Five coalitions representing more than 150 labor, faith and immigrant rights organizations worked closely with Spanish-language media to publicize the call to rally, according to Angelica Salas of the Coalition for Humane Immigrant Rights of Los Angeles.

"There was unanimous sentiment nationally and locally that we have to mobilize strong on May 1," Salas said. "It's a message to President Obama that we want immigration reform and an end to massive deportations of our community, and a special message to Republicans to stop getting in the way of reform and supporting hateful laws in Arizona."

But Ira Mehlman of the Federation for American Immigration Reform, a nonprofit group that supports tighter controls on illegal immigration, said most Americans don't support that message.

"What the public wants is enforcement of our immigration laws," Mehlman said. "They don't want people who break the law to be rewarded."

At the march's City Hall endpoint, Los Angeles Mayor Antonio Villaraigosa took the stage to raucous cheers. Speaking in English and Spanish, he called Los Angeles a "bilingual city" and expressed strong support for immigrants' rights.

Afterward, Mahony took the microphone. "Everyone in God's eyes is legal," he said. "We are all standing with our immigrant brothers and sisters."

Police reported only two arrests for minor offenses as the orderly crowd marched under sunny skies. Street vendors hawked American flags and bacon-wrapped hot dogs with onions and peppers. Union members blew horns and chanted "no human being is illegal" over the rhythmic melodies of a mariachi band.

In a major theme of the day, one man wore a white T-shirt reading "Todos Somos Arizona," or "We Are All Arizona."

Leon Franco, 38, a Sylmar construction worker who installs tile and marble flooring, draped an American flag around himself as he prepared to march Saturday morning.

"In Mexico, there's no way to get ahead," said Franco, a legal U.S. resident from the Mexican state of Hidalgo who moved to the United States in 1993. "Back home, I had a very poor life. If it wasn't for this country, I don't know where I'd be."

A year ago, Franco's wife, Rosa Moreno, an illegal immigrant, was arrested in Los Angeles and deported to her home state of Sonora in Mexico. Since then, Franco said, he has had to be "mother and father" to his stepson, Daniel Estrada, 14, and son, Johnny Franco, 12.

"My kids would like to have their mother here with them," he said. "I'm here because we don't want to happen to other kids what has happened to these two," pointing to his sons.

Morena Villanueva, 42, a Guatemala native, an illegal immigrant and a former carwash worker, held up a banner that read: "Wash away injustice."

She said her son, Luis Humberto Robles Villanueva, 21, was killed Thursday in Guatemala, and tearfully told how she couldn't return home to bury him.

"If I go back to Guatemala, I could never come back," she said. "My hope is that another parent will never have to suffer the way I have, to be unable to bury their child because they are illegal."

Victoria Vergara, a 53-year-old Mexico native and U.S. resident for 27 years, stood with a group of workers from the Westin Bonaventure and other hotels. Her brother, an illegal immigrant who runs a used-car business in Chicago, is afraid U.S. authorities will shut down his business and deport him after more than two decades here, she said.

"I was lucky. I was able to get amnesty in the 1986 law and now I'm an American citizen," she said. "We want President Obama to know that it's time to help these hard-working people who don't have papers, who have worked hard all their lives in this country and want to be good Americans."

The marchers also included African American union members, Korean drummers dressed in colorful traditional garb and even a white educator hoisting a sign that read "Gringos for Immigrants' Rights."

One illegal immigrant from South Korea, who asked to be identified by his first name, Jeff, said he came to protest the "broken-down immigration system."

"This does not just affect Latinos," said Jeff, wearing a white shirt that crossed out the word "minutemen." "This affects all communities."

In the hot seat of Arizona, rallies in Tucson and Phoenix drew hundreds of protesters.

In Tucson, organizers released a flock of doves and hundreds of white balloons, and Aztec dancers performed. Rally speakers included labor organizer Dolores Huerta and singer Linda Ronstadt.

Rep. Raul Grijalva, the Arizona congressman who has called for an economic boycott of the state, was received with boisterous cheers. "We are going to fight this law," he told the crowd.

A couple of dozen counter-protesters carried signs that read "Deport Illegal Mexicans," "Remember the Alamo, Mexico," "Boycott Mexico" and "Mexico Out of US."

Claudia White, 56, a Tucson resident and naturalized Mexican immigrant who organized the counter-protest, said she supported the Arizona law because she worried about the consequences of what she called "open-border policies." Recent immigrants, she said, show "less of an interest in how this country was originally set up - where everybody is an individual and doesn't identify as part of a group or a block or a race."

In Phoenix, where many activists were too exhausted by the fight against the bill to plan a unified event, a few thousand people poured onto the broad lawn in front of the state Capitol for what became a sort of daylong festival against SB 1070.

Vendors sold ices and mangoes, anarchists handed out literature about the right of indigenous people to travel freely, and families wheeled strollers carrying toddlers who chanted "Si se puede!"

A handful of people supporting the law trickled in during the day and often had to leave under police escort after being surrounded by agitated demonstrators.

Amelia Sally, a 35-year-old customer service representative, held a sign that read: "Got Your Papers? If So ... Welcome." She was disheartened at the way demonstrators around the country were bashing her state.

"Arizona's finally taking a stand," she said. "We've been begging for help."