BOSTON (CBS/AP) — Thousands of people, opposed to separating migrant families attempting to come into the United States, gathered in Boston on Saturday for two planned protests.

Saturday’s “Rally against Family Separation” began with 11 a.m. with speeches at City Hall. U.S. Senators Elizabeth Warren and Ed Markey and Congressman Joe Kennedy III were among the attendees.

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Warren said she had spoken with “mothers who have no idea where their children are and mothers who told me that at night, they believe they can still hear their children cry. I spoke with ICE officials who have no idea how they are going to reunite babies scattered all across this country with their mothers.”

Several protesters held signs criticizing President Trump and his administration on immigration issues, while Democratic lawmakers including Markey blasted the president during the rally.

“You cannot beg for freedom, you have to fight for freedom and that is what we are doing here in Boston,” said Markey, who is planning to visit detention and processing facilities in Port Isabel, McAllen, and Brownsville, Texas this weekend.

While at the border, Markey plans to deliver hand-made cards, pictures, and messages of support created by children in Massachusetts to the children and families being detained.

In a tweet on Saturday afternoon, President Trump defended his strong stance on illegal immigration.

“When people come into our Country illegally, we must IMMEDIATELY escort them back out without going through years of legal maneuvering,” Trump tweeted. “Our laws are the dumbest anywhere in the world. Republicans want Strong Borders and no Crime. Dems want Open Borders and are weak on Crime!”

The crowd then marched to Boston Common, where a large rally took place. The protest is timed with other protests nationwide and is also meant to oppose the Trump administration’s ban on travelers from certain Muslim-majority nations.

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During the rally, Brazilian immigrant Sirley Silveira Paixao sobbed.

The 30-year-old surrendered herself and her son Diego for asylum at the U.S. and Mexico border in May. They were separated soon after by U.S. Customs and Border Protection.

Through an interpreter, Paixao said of her son: “He would always ask me, ‘Mom, what date can you take me home?’ And I couldn’t promise anything, because I don’t know.”

She visited her son at an Office of Refugee and Resettlement run facility in Chicago, but was told he would not be released.

The second demonstration started Saturday afternoon with a march from Wellington Common Park to the South Bay House of Correction, a county jail in Boston which houses undocumented immigrants apprehended by federal officials.

Organizers demanded local government agencies stop cooperating with federal immigration authorities. The Suffolk County Sheriff’s Department said a total of 20 people were arrested without incident.

Before either of the rallies, a Brazilian mother living in Massachusetts who reunited with her 9-year-old son on Thursday in Chicago made an appearance at City Hall. The pair had been separated for weeks after crossing the U.S.-Mexico border.

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(© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)