More than 2,000 migrant children remain separated from their parents from the Trump administration's zero-tolerance immigration policy, and some lawmakers are calling for action.

Sen. Charles Schumer (D-New York) is calling for one person to be appointed to speed up the reunification process.

"Right now there are thousands of kids lost in limbo who await reunification with their parents and there are various agencies that are in charge," Schumer says. "The kids under the jurisdiction of Health and Human Services, the parents under the Justice Department."

Outrage against the policy that led to family separations continues on both sides of the aisle. But President Donald Trump hasn't wavered from his stance, despite signing an order to make changes to the process. He took to Twitter Sunday with several tweets on immigration, saying in part, "We cannot allow all of these people to invade our country. When somebody comes in, we must immediately, with no judges or court cases, bring them back from where they came."

Patrick Young, a Hofsta Law professor and program director for the Central American Refugee Center, says that's not legal.

"With those people who have a credible fear of persecution in their home country, that's illegal to do," Young says. "The law provides that they will have their day in court. The president cannot simply rewrite the laws based on his whim."

He expects the crisis at the border to continue unless Congress, the courts and the president take some kind of longer-term action.

According to the Department of Homeland Security and Health and Human services, family reunifications will only happen once the parent's deportation proceedings are completed.