Jayapal said she was with a group of over 500 women when she got arrested.
The Illinois Democrat, who recently gave birth to baby girl named Maile, joined Democratic colleagues Sens.
The arrests have been peaceful so far, with the protesters not arguing with Capitol police officers during arrests and no cuffs being put on them.
Almost 600 activists, protesting Donald Trump's "zero-tolerance" policy against illegal immigrants, have been arrested after staging an occupy sit-in at the Hart Senate Office building in the nation's capital.
The protesters, mostly women dressed in white, sat on the Hart Senate Office Building's marbled floors and wrapped themselves in metallic silver blankets similar to those given to migrant children separated from their families by USA immigration officials.
The protest, organized by a coalition of organizations including the Women's March and local immigrant advocacy group Casa de Maryland, was meant to demand the abolishment of Immigration and Customs Enforcement and an end to family detentions for migrants crossing the southern border.
According to reports, more than 500 people were arrested by the Capitol Police when they were having their sit-in protest at the Senate Hart Office building.
The largest demonstration on Thursday saw the 90-ft atrium of the Senate Hart Office building overrun by hundreds of women who sat on the floor pumping their fists in the air.
Congresswoman Pramila Jayapal, the first Indian-American woman to be elected to the US House of Representatives, has been arrested here during a protest against the Trump administration's "inhumane" "zero-tolerance" border policy.
Jayapal says she and other protesters were "here to fight for our families to be free, to fight for the ability of our kids to be with their parents - not in cages, not in prison, but able to live their lives free, safe and secure". Kirsten Gillibrand also appeared at the demonstration, calling it "an wonderful protest of women speaking out to be heard".
Under Trump's "zero tolerance" policy, the government has begun prosecuting all migrants caught entering the country without authorization.