Congressional Democrats joined protests of the Trump administration’s “zero tolerance” immigration policy Saturday, fanning out from detention centers to protests to party conventions and calling for an end to the practice of separating migrant families.

McAllen, Tex., a city on the U.S.-Mexico border, played host to 25 Democrats who wanted to see a detention center for themselves. They came out with stories of children in Mylar blankets, sitting on concrete floors, and told reporters that the situation had to be remedied by congressional action.

“I was reminded of my parents’ experience in internment camps during World War II,” said Rep. Mark Takano (D-Calif.).

“Child abuse is a violation of human rights,” said Rep. Barbara Lee (D-Calif.). “We need the United Nations coming down.”

Another delegation, to Florida’s Homestead shelter, brought four House Democrats and Sen. Bill Nelson (D-Fla.) together to inspect conditions; five local lawmakers were denied entry after being told that they needed to request a visit in advance. Rep. Debbie Wasserman Schultz (D-Fla.), who led the delegation, told reporters that 10 children inside the shelter had been separated from families.

There was a different kind of delegation in Tornillo, Tex., a town near El Paso, where the administration has announced the construction of a tent city for immigrant detention. Three Democrats and three Republicans, led by Rep. Brian Fitzpatrick (R-Pa.), headed down to see what was being put together — and did so the day before a planned protest, organized by opponents of the policy.

“I firmly opposed the inhumane practice of separating children from their parents at the border,” Fitzpatrick said in a statement. “While I am hopeful that the President’s executive order will end the practice of separating families awaiting court proceedings, we must ensure that this order is properly carried out.”

In general, Democrats were doing most of the talking. At the Nevada Democratic Party’s convention in Reno, Sen. Elizabeth Warren (D-Mass.) told activists that the administration had “decided to inflict as much pain as they can on people coming to the United States” and that Democrats would not respond to him by making a deal.

“His administration has ripped children from the arms of their mommies,” Warren said. “He has signed off on locking up small children in wire cages. He shrugged off the problem of reuniting thousands of children who’ve been taken away from their mothers and fathers. He’s called for cutting legal immigration in half and has made asylum harder for Iraqi translators who helped our soldiers in combat. He’s broken America’s promise to give dreamers a chance for a better future. And he’s turned his back on thousands of temporary protected status recipients, who have been living, working and contributing to the United States.”

Warren, who is up for reelection this year in her home state, was one of several candidates taking aim at the policy. On Friday, at the Texas Democratic Party convention, Rep. Beto O’Rourke (D-Tex.) explained why family separation had become a flash point in his Senate campaign.

“There are 2,500 children who have been taken from their parents in all of our names,” O’Rourke said. “We put them in tent cities, like the one in Tornillo. We separated them with no idea when or if they would ever be reunited. It is up to us, the people of Texas, to continue the fight and stop family separation.”

Other candidates spent the weekend seeing the situation on the border for themselves. California state Sen. Kevin de Leon, who is challenging Sen. Dianne Feinstein (D-Calif.) in November’s runoff, joined a Saturday march on the Otay Mesa Detention Facility near San Diego. Alexandria Ocasio-Cortez, who is challenging Rep. Joseph Crowley (D-N.Y.) in a June 26 primary, left New York to join a planned Sunday protest in Tornillo.