An investigation by The Guardian and the Fuller Project revealed nearly a dozen U.S. citizen children born to immigrant mothers over the past year were not provided birth certificates before being deported.

As reporting by The Daily Beast highlighted Friday, a rule instituted during the coronavirus pandemic allows Customs and Border Protection (CBP) to turn would-be migrants away without first allowing them to be considered for asylum or other programs.

In the case of the children born in the U.S. and parents facing deportation, the new investigation found a Haitian mother and her days-old baby slept on the side of a road in Mexico after being dropped off there by CBP agents. Lawyers believe there may be more cases than have been recorded since many fast-track deportations happen to people without the help of attorneys.

The Biden administration has signaled openness to revising the rule—instituted under the Trump administration—in question, but has yet to do so.