President Donald Trump threatened on Friday to veto the $1.3 trillion omnibus spending bill already passed by Congress, only hours before government funding would lapse.

The about-face comes a day after White House officials issued public assurances the president would sign the legislation, despite his misgivings about it. The government will shut down at 12:01 a.m. Saturday if Trump does not sign a funding bill into law.

In a tweet, Trump said he is “considering a VETO” because the proposal does not extend protections for hundreds of thousands of young undocumented immigrants or fully fund his proposed border wall.

I am considering a VETO of the Omnibus Spending Bill based on the fact that the 800,000 plus DACA recipients have been totally abandoned by the Democrats (not even mentioned in Bill) and the BORDER WALL, which is desperately needed for our National Defense, is not fully funded.

— Donald J. Trump (@realDonaldTrump) March 23, 2018

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The President’s tweet throws more chaos into the process to keep the government running, even after it looked Friday morning like Trump’s signature would only be a formality. Office of Management and Budget Director Mick Mulvaney answered “yes” on Thursday when asked if Trump would sign the bill.

“Why? Because it funds his priorities,” he told reporters.

Many lawmakers have already left Washington, and some are attending the funeral of longtime Rep. Louise Slaughter, who died last week. The Senate had adjourned and was not expected to take up legislative work again until April 9.

The legislation, which both chambers of Congress passed with bipartisan support, would fund the government through the end of September. It would significantly boost military spending and increase funding for border security, infrastructure and efforts to fight the opioid epidemic, among other programs.

It also includes measures meant to strengthen gun sale background checks and improve school safety.

While Trump cheered the military funding levels, he was apparently irked by the level of border security funding. The legislation would boost border enforcement funds by about $1.6 billion, to go toward surveillance technology and fencing along the border with Mexico. While Republicans have said the bill funds Trump’s “wall,” the money goes to fencing structures similar to ones that already exist.

The president, who has tried to end the Deferred Action for Childhood Arrivals program, reportedly wanted $25 billion in long-term wall funding in exchange for protections for the young immigrants. Democrats and some Republicans have sought to extend the DACA program. Trump reportedly did not want to give up to 1.8 million immigrants a pathway to citizenship as part of the deal, as Democrats wanted.

At least one Republican who opposed the spending bill encouraged Trump to torpedo it. Sen. Bob Corker, R-Tenn., told Trump to “please” veto the legislation, calling the spending levels “grotesque.”

Please do, Mr. President. I am just down the street and will bring you a pen. The spending levels without any offsets are grotesque, throwing all of our children under the bus. Totally irresponsible. https://t.co/np7BmP1AkB

— Senator Bob Corker (@SenBobCorker) March 23, 2018

The hardline conservative House Freedom Caucus also urged the president to oppose the legislation on Wednesday, the day of its release. The group argued the bill did not put enough funding toward border security and criticized the lack of a measure to pull funds from Planned Parenthood, among other provisions.

House Speaker Paul Ryan, R-Wisc., had worked this week to win Trump’s support for the plan. He describes it as a win for the president because it boosts Defense Department funding by about $80 billion, authorizes more money to fight the opioid crisis and puts more funding toward border enforcement.

“This funds the wall, fixes the military, fights opioids and does the things that we said,” Ryan said Thursday on Fox News’ “Fox & Friends,” a show Trump frequently watches and tweets about.

Ryan also went to the White House on Wednesday as Trump was unsure about whether to support the spending bill. After the president spoke with Ryan and Senate Majority Leader Mitch McConnell, R-Ky., the White House issued a statement saying he backed the legislation.