President Trump said he found inspiration for his long-stalled plan to build a wall along the southern border in an unlikely spot — a memorial to 9/11 victims in Shanksville, Pa.

In a 45-minute interview with Hill.TV on Tuesday, Trump said he was impressed by the walls that comprise the Flight 93 National Memorial, constructed to honor the 44 passengers and crew who died fighting al-Qaeda terrorists who hijacked their airplane during the Sept. 11 attacks in 2001. Trump spoke at the memorial last week, on the 17th anniversary of the attacks that killed nearly 3,000 people.

"They built this gorgeous wall where the plane went down in Pennsylvania, Shanksville. And I was there. I made the speech. And it's sort of beautiful, what they did is incredible," Trump said on Hill.TV. "They have a series of walls, I'm saying, it's like perfect. So, so, we are pushing very hard."

Trump also repeated the misleading claim that his administration has already begun building the border wall, saying in the interview, "We've started an 80-mile stretch." According to Factcheck.org, the $1.6 billion Congress approved in late March is designated to replace existing border fencing deemed inadequate or dilapidated, and to add some fencing in new areas.

"The new barriers are not concrete and not like any of Trump's wall prototypes," according to Factcheck.org's Robert Farley.

Trump also told Hill.TV he was planning to use his executive powers to do more on immigration in the coming weeks, but was vague on the details.

"I'll be doing things over the next two weeks having to do with immigration, which I think you'll be very impressed at," Trump said.

The Trump administration has drawn controversy for attempting to rewrite the rules of a 21-year-old agreement in order to detain children who cross the Mexican-U.S. border with their parents indefinitely as the government works on their immigration cases. Currently, under the Flores settlement, children have been permitted to be held for 20 days.

According to government figures obtained last week by MSNBC correspondent Jacob Soboroff, of the 2,654 children separated from their parents under the administration's "zero tolerance" policy, 211 remain in government custody without their parents. Six are under the age of five.

About 12,800 migrant children are currently being detained at federally contracted shelters, a dramatic increase from the 2,400 children that were in government custody in May 2017, according to data obtained by the New York Times.

"The huge increases, which have placed the federal shelter system near capacity, are due not to an influx of children entering the country, but a reduction in the number being released to live with families and other sponsors, the data collected by the Department of Health and Human Services suggests," wrote Times reporter Caitlin Dickerson.