President Donald Trump has reportedly been pushing to bring back a policy of separating migrant children from their parents at the southern U.S. border, NBC News reported Monday.

Since early this year, Trump has been asking his administration to reinstate its previous family separation policy, NBC reported, citing three U.S. officials with knowledge of White House meetings. One senior administration official told the outlet that Trump appeared to think it was the best deterrent against migrants seeking to come to the U.S.

CNN similarly reported that Trump has been seeking for months to bring back the policy but on an even broader scale than it had been implemented previously. Citing unnamed senior administration officials, the outlet said Trump wanted migrant families separated even if they came in at ports of entry or were asylum-seekers. (The previous policy criminally prosecuted migrant parents who had crossed the border outside ports of entry, resulting in separation from their children, who were often then detained elsewhere.)

Both outlets said outgoing Homeland Security Secretary Kirstjen Nielsen, who resigned Sunday , had been pushing back against the presidents request, citing court challenges against the policy.

And New York Times White House correspondent Michael Shear said in a tweet that he could confirm NBCs report that Trump wanted the policy back despite his signing an executive order last June to end it.

HuffPost reached out to the White House, but did not immediately receive a response.

The Trump administrations hardline zero tolerance immigration policy, announced last May , referred for criminal prosecution all migrants crossing the border at unofficial points of entry, leading to the separation of thousands of children from their parents. The policy received widespread criticism and sparked protests nationwide.

Trump signed an executive order in late June reversing the policy. A January report from the Department of Health and Human Services found the administration may have separated thousands more kids from parents at the border, and it does not know how many or whether they were reunited.