President Donald Trump corrected his Chief of Staff John Kelly after he said that the president had “evolved” on the wall.

“There’s been an evolutionary process that this president has gone through,” Kelly said in an interview with Fox News host Bret Baier, pointing out that Trump had “very definitely changed his attitude” towards DACA recipients and the wall.

But Trump pushed back on Twitter against the suggestion that he had evolved on the wall.

“The Wall is the Wall, it has never changed or evolved from the first day I conceived of it,” Trump said.

The Wall is the Wall, it has never changed or evolved from the first day I conceived of it. Parts will be, of necessity, see through and it was never intended to be built in areas where there is natural protection such as mountains, wastelands or tough rivers or water….. — Donald J. Trump (@realDonaldTrump) January 18, 2018

He explained that parts of the wall would be “see-through” and that it was never meant to stretch across the whole 2,000-mile border where there were already natural barriers.

Kelly said that he and border experts told Trump that 800 miles of wall would “suffice” which included 600 miles of existing fencing.

“He has evolved in the way he’s looked at things,” Kelly said. “Campaign to governing are two different things and this president has been very, very flexible in terms of what is within the realm of the possible.”

Kelly also suggested that the wall would not be paid “directly” by Mexico, something that Trump also corrected.

“The Wall will be paid for, directly or indirectly, or through longer term reimbursement, by Mexico, which has a ridiculous $71 billion dollar trade surplus with the U.S.,” he wrote. “The $20 billion dollar Wall is ‘peanuts’ compared to what Mexico makes from the U.S. NAFTA is a bad joke!”

….The Wall will be paid for, directly or indirectly, or through longer term reimbursement, by Mexico, which has a ridiculous $71 billion dollar trade surplus with the U.S. The $20 billion dollar Wall is “peanuts” compared to what Mexico makes from the U.S. NAFTA is a bad joke! — Donald J. Trump (@realDonaldTrump) January 18, 2018

Trump added that without wall funding there would be no DACA deal.

“We need the Wall for the safety and security of our country,” he wrote. “We need the Wall to help stop the massive inflow of drugs from Mexico, now rated the number one most dangerous country in the world. If there is no Wall, there is no Deal!”