President-elect Donald Trump might quickly make good on a campaign promise to build a wall between the U.S. and Mexico if Republicans in Congress agree to include the money in a fiscal 2017 spending package, according to media reports.

Trump early Friday said that Congress would have to appropriate money so construction could get underway but it would be paid back, tweeting: “The dishonest media does not report that any money spent on building the Great Wall (for sake of speed), will be paid back by Mexico later!”

But a House Appropriations Committee aide told CQ Roll Call on Thursday night that the committee had not heard from the Trump transition team about building a wall with taxpayer money rather than billing Mexico, as Trump promised during his campaign. The Senate Appropriations Committee had no comment, nor did House and Senate GOP leadership aides.

The Associated Press reported that House Republican leadership is working with the transition team to consider building the wall using the authorization of a 2006 law that George W. Bush signed but Congress didn’t completely fund.

That law called for a double-layer, 700-mile-long stretch of fencing along the divide, though that was later revised legislatively for flexibility. CNN and Politico said Trump would ask Congress to appropriate taxpayer funds to pay for better border security.

Unnamed sources in the reports emphasized no decisions have been made and Republicans had little comment.

“The administration is still putting together its team and no decisions have been made. Securing the border is a priority House Republicans share with the incoming administration and we expect to address it,” an aide to House Majority Whip Steve Scalise of Louisiana, said when asked to comment on the reports or provide any information.

Lawmakers could include payment for border infrastructure using the fiscal 2017 spending process, since current government funding for fiscal 2017 that began Oct. 1 expires April 28. Trump asked Congress late last year to delay final spending decisions until he took office.

[Ryan on Border Wall: ’You Have to Have Physical Barriers′]

Lawmakers could instead include spending in other legislation, such as a supplemental appropriations bill or a fiscal 2018 spending measure. But the quickest regular appropriations legislation lawmakers can move once Trump enters office would be a fiscal 2017 spending bill.

The fence law signed roughly a decade ago that lawmakers are examining calls for both a physical and “virtual” fence — including aerial drones, ground sensors, and cameras. House Majority Leader Kevin McCarthy of California, said in a conversation with reporters after Trump was elected that the GOP might not build a full border wall but would secure the border.

It’s unclear how much support Trump’s plans would have from appropriators. At a House Appropriations Committee hearing last spring, the Obama administration’s border security chief told members that a solid wall was not an effective use of funds to protect the border.

Democrats on the committee were similarly skeptical: Texas Rep. Henry Cuellar called the border wall a “14th-century solution to a 21st-century problem.”

The 2,000-mile border currently has 702 miles of mostly single-layer fencing installed. The 2006 law authorized two layers of fencing but was later amended. Republicans, and Trump himself, are now talking about a combination of fencing and wall.

The 2006 measure set a May 30, 2007, deadline for installing cameras, and a May 30, 2008, deadline for completing fencing along a 361-mile portion of the border from Calexico, California, to Douglas, Arizona, and a Dec. 31, 2008, deadline for fencing that would run from 15 miles northwest of, to 15 miles southeast of, the Laredo, Texas, port of entry.

Trump estimated in an MSNBC interview in February 2016 that building a wall along the U.S.-Mexico border, about 35 to 40 feet high, would cost $8 billion, though that figure was called into question by independent media reports and fact checkers.

A complication to Trump’s promise to force Mexico to pay for a wall to divide the two countries: the majority of the 2,000-mile border lies on the Rio Grande. In Texas, that means almost all of the wall would have to be built on U.S. soil, and most of the wall would cut through private property. Typically when governments look to build infrastructure — freeways, for example — along private property, the project can get tied up in a complicated, potentially costly right-of-way acquisition process.

Ryan McCrimmon, Dean DeChiaro, Jonathan Miller and Jennifer Shutt contributed to this report.