Donald Trump explained Saturday that his signature campaign promise to have Mexico pay for a new massive border wall was really more of a request for a refund.

Proposing a new piece of legislation called the “End Illegal Immigration Act,” the Republican nominee told a crowd in Gettysburg, Pennsylvania that Mexico would “reimburse” the U.S. for the cost.

“The End Illegal Immigration act fully funds the construction of a wall on our southern border,” he said in a speech laying out his vision for the first 100 days of a Trump presidency.

“Don’t worry about it,” he cautioned the crowd in an aside, holding up a finger. “Remember I said that Mexico is paying for the wall.”

An audience member whooped.

“With the full understanding that the country of Mexico will be reimbursing the United States for the full cost of such a wall, okay?” Trump continued, to a more muted cheer.

If elected, Trump would need to persuade Congress to draft a law to fund his proposal. The Republican nominee has promised that the cost for the “big, beautiful” 50-foot structure would not cost more than $12 billion dollars. Fact-checkers have put forth higher estimates, ranging up to $25 billion.

Mexican president Enrique Peña-Nieto has also insisted that his country would not cover the cost of the wall. After Trump told reporters the two did not discuss payment during his impromptu visit to Mexico, Peña Nieto said he made it “very clear” to the Republican nominee that Mexico would “never” pay for it. The two politicians ended up engaging in a Twitter war over what exactly was said in conversation.

Earlier in the election cycle, the GOP nominee proposed funding the wall by taxing the remittances immigrants send to family members in their home countries.