Story highlights US taxpayers will have to pay for construction

Trump has said Mexico will reimburse the US for the cost of the wall

Philadelphia (CNN) Congress may pay for the border wall through a special spending bill being hashed out over the next two months, footing the cost of President Donald Trump's priority before seeking any refund from Mexico, Republican lawmakers said Wednesday.

"We're going to pay for it and front the money up," House Speaker Paul Ryan said on MSNBC Wednesday evening.

"Point is, he has a promise he made to the American people, which is to secure our border," Ryan added of Trump. "A wall is a big part of that. We agree with that goal and we will be working with him to finance construction of the physical barrier, including the wall, on the southern border."

Earlier, Ryan told lawmakers gathered in Philadelphia for a private retreat this week that they could pay for the wall through a supplemental appropriations bill -- a spending measure that would be dedicated just to the wall, according to Republicans in the room and a GOP lawmaker.

"(Ryan) talked about the supplemental budget coming this spring to push that along. The President said he's going to get reimbursed one way or the other and we accept that. Meanwhile, we do have to pay our bills," Rep. Chris Collins, a New York Republican and Trump ally, said Wednesday.

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