NEW YORK -- Thousands of activists armed with flags, puppets and cow bells took to the city's streets on Wednesday to rally for immigration reform and labor rights as part of worldwide May Day protests.

In a scene reminiscent of Occupy Wall Street's heyday, protesters marched in downtown Manhattan toward City Hall waving banners and banging on drums. The peaceful crowd was largely composed of unions and immigration reform groups, with some anti-capitalism and Occupy protesters mixed in.

"We're here because we are demanding legalization," said Gonzalo Venegas, a 28-year-old member of a hip-hop activist group from the Bronx, who performed in front of the crowd during a rally in Union Square. "For us, the idea of immigrant rights and workers' rights goes hand in hand."

Bands of protesters joined marches and rallies throughout the city as the day wore on. The May Day rallies, a nationwide ritual, traditionally attract many labor leaders and elected officials.

Paper rats on sticks -- intended to symbolize abused migrant workers -- bobbed along Sixth Avenue as about 200 protesters set off from Bryant Park, chanting: "What do we want? Justice! When do we want it? Now!"

"Every May Day, more groups that have historically considered themselves separate from one another come together," said 26-year-old Becky Wartell, who was carrying a tall puppet of the Statue of Liberty.

Near Tompkins Square Park, where an anti-capitalist march converged earlier in the day, police said Wednesday evening that eight people were arrested on charges of disorderly conduct for obstructing traffic.

Immigration reform took on special significance this year as Congress considers sweeping legislation that would bring many of the estimated 11 million people living in the U.S. illegally out of the shadows.

In Union Square, some speakers alternated between English and Spanish for the benefit of the diverse crowd, which included a sizable portion of immigrant protesters who did not speak English.

Venegas, who was born in the United States after his family members fled Chile as political refugees, expressed frustration over the fact that he is a U.S. citizen but his brother and mother are not.

"The new Gang of Eight proposal for immigration reform is pretty much offering crumbs," he said, "and creating a second-tier class of citizenship."

Later in the evening, after speeches at City Hall by union leaders and immigration advocates, a few dozen protesters gathered in Foley Square and Zuccotti Park, the site of Occupy's former encampment, which was disbanded in late 2011. The gatherings were peaceful.

"The dreamers, the workers -- all immigrants need to have a full life now," said Mariano Munoz, a member of the Immigrant Worker Justice Group, which helped organize the protest. "They need full, basic human rights."