President Donald Trump has said that his proposed border wall doesn't necessarily need to cover the full 2,000-mile border between the U.S. and Mexico.
Trump told reporters on Air Force One that natural barriers meant that less than half that distance would need to be protected, the Los Angeles Times reported.
During the presidential election campaign, Trump often described building a wall that would be 30 feet high.
"You don't need 2,000 miles of wall because you have a lot of natural barriers," the president said, according to the Times.
"You have mountains," he added. "You have some rivers that are violent and vicious. You have some areas that are so far away that you don't really have people crossing. So you don't need that."
"You'll need anything from 700 to 900 miles," he added.
Trump also explained that it would be necessary to see through the wall, leading to speculation that he is now in favor of the type of fences built under the Obama and Bush administrations.
"You know, we've already started the wall because we're fixing large portions of wall right now," Trump said. "We're taking wall that was good but it's in very bad shape, and we're making it new."
Groups who backed Trump in the election campaign, including the Federation for American Immigration Reform, expressed concern that he is retreating from his promises.
"We expect he will fulfill the promises he made and we are going to continue to hold him accountable," Ira Mehlman, the group's spokesperson, told the Times. "He needs to push Congress to do these things he was elected for. Now it's time he deliver."
Mehlman also wants Trump to abolish the Deferred Action for Childhood Arrivals program, which enables around 800,000 people who came to the country as children to remain in the U.S. Trump confirmed on Air Force One that he would make a decision on whether to keep the program in place.
Department of Homeland Security Secretary John Kelly told the Congressional Hispanic Caucus on July 12 that the DACA program could be ended due to pending legal action. Officials from a number of states are threatening to sue the federal government if it does not repeal DACA by Sept. 5.
"This is what he's being told by different attorneys, that if it goes to court it might not survive," DHS spokesman David Lapan told the Washington Post. Unless Congress passes a law protecting DACA, "they're leaving it in the hands of the courts to make a decision."
Trump promised during the campaign to rescind DACA.