"These women understand, they're from all over the country". It is unclear what, exactly, precipitated the arrests.
Actress Susan Sarandon said she too was arrested on Thursday in Washington, where people had gathered in protest outside the Department of Justice.
Rep. Pramila Jayapal, D-Wash., said she was arrested during the protest.
"As a woman and as a mother, I refuse to stay silent as parents on the border are separated from their kids", said Tamika Mallory, co-chair of the Women's March, who was one of those arrested.
She also pledged to participate in another protest this weekend, writing on Twitter, "June 30 we're putting ourselves in the street again".
Congresswomen Pramila Jayapal, D-Seattle, was arrested along with hundreds of other women during an immigration protest at the nation's capital. The group took over the center of the Hart Senate office building to protest the Trump administration's "zero tolerance" policy and family separations at the U.S. -Mexico border, according to Jayapal.
Hundreds of children remain separated from their parents in shelters throughout the US.
About 575 people, mostly women, were charged with demonstrating unlawfully.
Thursday's march was one of several Washington demonstrations this week to rebuke Trump's immigration policies. Soon after, protesters were lined against a wall in small groups and police confiscated their blankets and signs.
"What the administration is doing right now is morally wrong, it is inhumane and it has to stop", Gillibrand said.
She said that the last two weeks have been really consumed by this issue.
"People across my state of NY, all across the country are furious with this administration's policy to separate children from their parents", Gillibrand said.
The American Academy of Pediatrics (AAP) and the American Medical Association (AMA) have both spoken out against the Trump administration's practice of separating families, citing the grave psychological damage being done to both children and parents who have been forcibly separated-many after fleeing violence in their home countries.