Union leaders and immigrant advocates rallied in San Francisco on Monday, denouncing federal immigration raids and the detention of a California labor leader.

David Huerta, the 58-year-old president of Service Employees International Union California, was arrested Friday while protesting outside a business where federal law enforcement agents were investigating suspected immigration violations, authorities said.

He was released from federal custody Monday on a $50,000 bond after a hearing in federal court in Los Angeles.

Union members and immigrant advocates led rallies in cities from Los Angeles to Chicago to New York to call for Huerta’s release. In Boston, hundreds of people gathered in City Hall Plaza, with protesters shouting “Free David, free them all.”

His arrest has become a rallying cry for immigrant advocates across the country, calling for an end to President Donald Trump’s immigration crackdown.

This comes as the Pentagon announced it will deploy about 700 Marines to Los Angeles on Monday to help National Guard members respond to immigration protests, officials said,

The state of California is also preparing to sue President Trump over his use of the Guard troops and demonstrators took to the city's streets for a fourth day.

The arrival of the National Guard followed two days of protests that began Friday in downtown Los Angeles after federal immigration authorities arrested more than 40 people that day across the city.