President Donald Trump’s threat to shut down the U.S. government if Congress doesn’t fund his campaign pledge to build a wall on the Mexican border appeared to send a shiver through the stock market Wednesday.

“If we have to close down our government, we’re building that wall,” Trump told supporters Tuesday night in Phoenix, at a meandering, campaign-style rally that saw him rail at the media, Arizona’s two Republican senators, and congressional Democrats.

Trump is seeking $1.6 billion to begin construction of the wall. The pledge to build a wall—albeit alongside a vow that Mexico would foot the bill—was Trump’s signature campaign pledge. Congress must pass a spending bill to keep the government open beyond the end of the current fiscal year on Sept. 30. Mexico has rejected paying for the construction of a wall and the proposal has little support in Congress, even among Trump’s fellow Republicans.

Market watchers said the remarks contributed to weakness across global equities, including a dip on Wall Street that saw the S&P 500 index SPX, -1.15% retreat 0.3% and the Dow Jones Industrial Average DJIA, -1.84% fall by 0.4%.

See:Here’s how stocks fared in past government shutdowns

Analysts, however, said the remarks also appeared to be part of Trump’s characteristic bluster and were unlikely to have a lasting effect—at least until the budget deadline approaches. Jasper Lawler, head of research at London Capital Group, called the move “basically a bluff by Trump to get his ‘Great Wall’ back on the agenda and show some political rebellion following his foreign policy capitulation in Afghanistan.”

Ultimately, Trump won’t want a government shutdown “because he feels compelled to put across the image of America ‘winning’ under his presidency,” Lawler said, in a note. “A government shutdown symbolizes failed leadership.”

The weakness comes a day after stocks gained ground after trending lower over the past two weeks, with some analysts crediting a news report citing progress by the White House and lawmakers on tax proposals, among the centerpieces of Trump’s promises for pro-business legislations. Some investors, however, have long questioned the overarching impact of Trump’s broader policy agenda on stocks and other financial markets amid dwindling expectations for quick action on tax policy and other measures that might stimulate economic growth.

See:Do stock-market investors really care about Gary Cohn and the Trump agenda?

Trump also expressed doubts about talks that are under way to renegotiate the North American Free Trade Agreement, telling the crowd, “I think we’ll end up probably terminating Nafta at some point.”

The Nafta remarks were also cited as a factor behind general weakness in equities and other assets perceived as risky, but were seen as a particular catalyst for weakness in the Canadian dollar USDCAD, -0.03% and Mexican peso USDMXN, +0.07% USDMXN, +0.07% though the Canadian currency subsequently regained its footing.

While Trump has previously threatened to end Nafta, this was the first time he’s made such a threat since negotiations started, noted Thierry Albert Wizman, global interest rates and currency strategist at Macquarie, in a note.

Again, analysts pondered whether Trump’s statements were negotiating tactics.

“No one can be sure whether the comments are a way for Trump to influence the negotiations, or whether he thinks that the negotiations are ‘just a formality’ and he means to scrap Nafta completely,” Wizman said.

Meanwhile, Fitch Ratings on Tuesday said it would review its triple-A U.S. debt rating if the debt ceiling isn’t raised, but said that a government shutdown wouldn’t have a direct impact on the rating.

The debt ceiling, a limit on the total amount of debt the U.S. government can owe, is a separate issue from the potential for a government shutdown. Treasury Secretary Steven Mnuchin has warned that he will run out of room for maneuver by the end of September, risking a default.

On Tuesday, Senate Majority Leader Mitch McConnell, whose relationship with Trump has soured after a failed effort to pass a health-care bill, said there was “zero chance” that the debt ceiling won’t be raised at an event in Kentucky with Mnuchin.