WASHINGTON (Reuters) – U.S. President Donald Trump said he would “totally be willing” to shut down the federal government unless Congress authorized $5 billion to fund his long-promised wall along the U.S. border with Mexico, according to a Politico interview published on Wednesday.

Trump also told the news outlet, in the interview conducted on Tuesday, that the $5 billion request would pay for physical barrier alone, and that additional funding would be needed for other border security measures.

In a separate interview with the Washington Post on Tuesday, the Republican president said that if Congress does not fund the wall he might try to get it done another way. He referred to his ordering of U.S. troops to the border in October to install “barbed wire and fencing and various other things.”

U.S. lawmakers must act to pass a spending bill by Dec. 7 to fund some government agencies, including the Department of Homeland Security that oversees the border and immigration.

Trump has not followed through on previous threats to shut down the U.S. government over the border wall funding. But with his fellow Republicans set to lose control of the House of Representatives in January following Democrats’ gains in elections this month, Trump’s comments have raised concern that this time he may not back down.

Republicans will maintain their control of the Senate next year but still, need some Democratic support to pass spending legislation.

Democrats have refused to support Trump’s border wall, which was a major part of his 2016 election platform, but have backed other border security measures.

Trump told Politico on Tuesday that he saw little need to work with Congress over immigration reforms to address the roughly 700,000 so-called Dreamers, young adults who were brought to the United States illegally as children.

Instead, he said he wants to see first how court challenges play out over an Obama-era program that allowed Dreamers to stay in the country.

If the courts ultimately rule against the program, then he would be willing to negotiate over “border security and everything else,” he told Politico.

Legislation to protect the Dreamers has so far failed to pass Congress.

(Reporting by Susan Heavey; Editing by Matthew Mpoke Bigg, Chizu Nomiyama and Frances Kerry)