Separating families at the southern border is not an option, according to Kevin McAleenan, the acting secretary of the Department of Homeland Security.

McAleenan told NBC News' Lester Holt in a recent interview that the Trump administration's zero-tolerance policy initiative was never intended to keep families apart. President Donald Trump appointed McAleenan to take over as acting secretary of the agency earlier this month following Kirstjen Nielsen's resignation from the post.

"I think the president has been clear that family separation is not on the table, and again this was a zero-tolerance prosecution initiative that was targeted at adults violating the law," McAleenan said during a clip of the interview at the DHS offices in the World Trade Center in New York City.



"They were always intended to be reunited," he added. "And really a better system, as I've said many times, would allow us to detain families together during fair and expeditious immigration proceedings and getting actual immigration results from courts, so that's what's missing from the current situation."

McAleenan previously served as commissioner of the U.S. Customs and Border Protection.

What's the backstory on the policy?

Last year, Nielsen made headlines after implementing a zero-tolerance policy that temporarily separated thousands of minors from their parents who had crossed illegally into the U.S. The courts later blocked the policy.

In June, Trump signed an executive order ending family separations.

U.S. officials reportedly told NBC that Nielsen was forced out of her position "in part because she'd refused to reinstate the policy of separating children from their families at the border."

What did McAleenan say about the effectiveness of the zero-tolerance policy?

In a portion of the interview not yet aired, Holt reportedly asked whether or not McAleenan believed zero-tolerance was an effective policy.

"So prosecuting violations of the law does have a consequence and it does deter behavior but it did not work if you lose the public trust," McAleenan responded, adding that from "an enforcement perspective, it's not worth it."