Former White House chief of staff John Kelly appeared to waver on several key Trump administration immigration policies on Wednesday, during an event at Duke University.

Kelly reportedly told the audience that building a wall "from sea to shining sea" would be a "waste of money."

He also appeared to back away from taking responsibility for the "zero tolerance" policy that separated thousands of migrant families, saying it "came as a surprise," according to The New York Times.

Former White House chief of staff John Kelly told an audience at Duke University on Wednesday that building a wall "from sea to shining sea" would be a "waste of money," according to The New York Times.

Kelly made the comments during a 90-minute question-and-answer session at the university in North Carolina, where the topics ranged from foreign policy, to the security clearance granted to President Donald Trump's son-in-law, Jared Kushner.

Like Kelly, the Trump administration has also backed away from some of Trump's more grandiose rhetoric about the wall, which he said during his campaign would span at least 1,000 of the US-Mexico border's 2,000 miles and be paid for by Mexico.

Currently, the Trump administration is trying to use a national emergency declaration to secure funding to build roughly 230 miles of wall.

Wednesday was not the first time Kelly has appeared less than enthusiastic about the way Trump has framed his efforts to build the wall. Shortly before he left the White House in December 2018, Kelly told The Los Angeles Times that the wall won't actually be a "wall."

Read more: Outgoing chief of staff John Kelly says Trump's 'wall' won't actually be a wall: 'To be honest, it’s not a wall'

"The president still says 'wall' — oftentimes frankly he'll say 'barrier' or 'fencing,' now he's tended toward steel slats," Kelly said. "But we left a solid concrete wall early on in the administration, when we asked people what they needed and where they needed it."

In this Nov. 1, 2018 photo, President Donald Trump walks in to the Roosevelt Room of the White House in Washington, to talk about immigration and border security. Associated Press/Susan Walsh

In an earlier incident, Kelly reportedly angered Trump when he told Democratic lawmakers in private that Trump had not been "fully informed" when he was campaigning on a promise to build the wall, and that Trump "evolved" on the issue and come to agree the wall wasn't necessary.

During his remarks on Wednesday, Kelly also discussed the controversial "zero tolerance" policy that forcibly separated thousands of migrant children from their parents. Kelly said the policy "came as a surprise" to him and to other officials, and he reportedly blamed then-Attorney General Jeff Sessions for the haphazard rollout.

But Kelly had been a staunch defender of the policy at the time, and even told NPR that the policy would serve as a "tough deterrent" for migrants, and that "the children will be taken care of — put into foster care or whatever."