The Department of Homeland Security says it knows the locations of all children separated from their parents under the Trump administration's "zero tolerance" immigration policy. Officials said Saturday night more than 2,000 separated minors remained in government facilities.

But it's not known how long the process to reunite families will take.

A new CBS poll finds 75 percent of Democrats say re-unifying separated families is a "high-priority, compared to 23 percent of Republicans.

Hundreds of protesters in Tornillo, Texas chanted "free the children" near the port of entry gates Sunday morning. The tent city is in a desolate part of the border.

The Department of Health and Human Services said in a release that they "have a process to ensure that family members know the location of their children and have regular communication after separation."

But federal public defenders in El Paso say that in a number of "zero-tolerance" criminal cases, their clients have not been told where their children are.

Shane McMahon, a federal public defender, says that when the president says the stories of grief are over-exaggerated at the border, he would respond "Mr. President, come to El Paso and I will show you stories that are real stories of grief and sadness. They're not phony and they're not made up for the people who don't know where their four-year-old child is."

On Saturday, a delegation of both Republican and Democratic politicians toured the site that's currently housing hundreds of unaccompanied teenagers.

Twenty-three of them were recently separated from their families, and there are at least seven girls inside.

U.S. Rep. Joaquin Castro, R-Texas, said what really struck him is "when you look around, we are in the middle of the desert and you have a tent. I think in many ways it's a monument to the failure of the fed government."

HHS also says separated children "are able to communicate (either telephonic or video depending on the circumstances) with their parent or guardian." CBS has confirmed that those calls are limited to twice a week, 10 minutes a piece.

"We need to make sure in Congress that the Trump administration provides a fully comprehensive list of every child and their parents so that we can then go an audit and make sure that everyone is reunited," Castro said.

The government says they know where all those separated children are, but what slows the process is confirming that the people who want to communicate with them are really parents or legal guardians.

Senate Minority Leader Chuck Schumer is calling for an immigration czar to oversee the reunification process from here on out.