There is virtually no chance that President Donald Trump’s proposed wall along the U.S.-Mexico border will be paid for by Mexico — despite his repeated campaign pledges — and now the White House is signaling that the massive construction project may not even take place inside U.S. territory.

Trump’s Interior Secretary Ryan Zinke made the media rounds this week to sell the president’s efforts to roll back environmental protections. The former Montana congressman promised a “very pro-Western” administration that plans to relax protections for threatened jaguars, which live in northern Mexico and parts of the U.S. Southwest, in order to build Trump’s border wall.

Advertisement:

But Zinke, as admitted to energy and environmental outlet E&E News, Trump’s wall may even have to be built on Mexican territory, not American territory, in accordance with the terrain along the border.

"The border is complicated, as far as building a physical wall," Zinke told E&E News’ Corbin Hiar. "The Rio Grande, what side of the river are you going to put the wall? We're not going to put it on our side and cede the river to Mexico. And we're probably not going to put it in the middle of the river."

According to international treaties signed between the U.S. and Mexico, the 1,200-mile long Rio Grande is the official border between the two countries.

Advertisement:

Zinke didn’t elaborate on how the wall would be built if it weren't located on the U.S. side of the Rio Grande or in the middle of the river. His comments are the first from a Trump administration official to suggest that the U.S. should build the wall on Mexican territory.

In an executive order on border security released in January, Trump called for “the immediate construction of a physical wall on the southern border.” According to Trump’s order, “‘southern border’ shall mean the contiguous land border between the United States and Mexico, including all points of entry.

The massive construction project has been estimated to cost as much as $22 billion — more than the $16 billion price tag that Trump often cited on the campaign trail. The White House has already requested $999 million from Congress to build 48 miles of the wall. But at least one Republican in Congress has already shot down Trump's chances of receiving any financing from Congress in the spending bill that must be passed by April 28 in order to avert a partial government shutdown.