Trump administration officials say they have no clear plan yet on how to reunite the thousands of children separated from their families at the border since the implementation of a zero-tolerance policy in which anyone caught entering the U.S. illegally is criminally prosecuted.

“This policy is relatively new,” said Steven Wagner, an acting assistant secretary at the Department of Health and Human Services “We’re still working through the experience of reunifying kids with their parents after adjudication.”

Federal officials say there are some methods parents can use to try to find their children: hotlines to call and an email address for those seeking information. But advocates say it’s not that simple.