President Donald Trump sounded pessimistic of making much progress Sunday toward ending the partial U.S. government shutdown, even hinting again that he may declare a national emergency to get funding for a wall along the U.S.-Mexico border, the issue behind the stalemate.

Trump is prepared to bypass Congress if necessary by declaring the emergency if he does not get the $5.6 billion in funding he wants to build the wall, his White House press secretary said.

Sarah Huckabee Sanders told Fox News Sunday that the White House has been looking at "every option available" to get the needed money, and she said Trump will do "whatever it takes to protect our borders."

Trump asserted on Friday that he could declare a national emergency to build the wall without congressional approval, but would first try a "negotiated process." Such a move is certain to draw legal challenges.

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U.S. President Donald Trump is considering declaring a national emergency in order to get his border wall funded. Disagreements about how to fund the wall have already led to a partial government shutdown that Trump is in no rush to end. 3:00

Sanders said Trump is "not going to stop" until he figures out the best way to protect U.S. citizens and that "whatever action he takes will certainly be lawful."

She spoke after a first round of talks between White House officials and congressional aides on Saturday made little progress toward ending the shutdown, now in its 16th day, with more discussions planned for Sunday afternoon.

Trump seemed to undercut his own team by saying on Sunday that he needed to deal directly with Democratic leaders who have been holding out on supporting the funding request.

"Ultimately, it's going to be solved by the principals," Trump told reporters at the White House before leaving for staff meetings at Camp David in Maryland as the shutdown headed into its third week.

Trump suggests direct, 3-way talks

"I don't expect to have anything happen at that meeting," said Trump about the talks today led by Vice President Mike Pence. "But I think we're going to have some very serious talks come Monday, Tuesday, Wednesday."

From Friday: Trump mulls declaring national emergency to get border wall funding

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The U.S. president suggested that he, House Speaker Nancy Pelosi and Senate Minority Leader Chuck Schumer could solve the impasse over money for a U.S.-Mexico border wall "in 20 minutes, if they want to. If they don't want to, it's going to go on for a long time."

Trump also asserted that he could relate to the plight of the hundreds of thousands of federal workers who aren't receiving paycheques, though he acknowledged they will have to "make adjustments" to deal with the shutdown shortfall. A day earlier, the president had tweeted that he didn't care, adding that "most of the workers not getting paid are Democrats."

New steel fence design?

He said he planned to call the heads of American steel companies in hopes of coming up with a new design for the barrier he contends must be built along the southern border. Trump had previously promised a concrete wall, but now says it could be made of steel slats. His administration has already spent millions constructing wall prototypes near the border in San Diego.

With the talks stalled, Pelosi, a California Democrat, said House Democrats intended to start passing individual bills to reopen agencies. The first would be the Treasury Department, to ensure people receive their tax refunds.

Democrats said the White House did not budge Saturday on the president's demand for the wall money. The White House said money was not discussed in depth, but the administration was clear about the need for a wall and the goal of resolving the shutdown all at once, not piecemeal.

Acting chief of staff Mick Mulvaney told NBC's Meet the Press that he believes Democrats "think they're winning the PR battle and they're willing to drag this out because they think it hurts the president." Democrats familiar with the meeting said the White House position was "untenable."

Showing 'he's not building a wall anymore'

A White House official said the meeting included a briefing on border security by Homeland Security Secretary Kirstjen Nielsen. Democrats sought written details from the Department of Homeland Security on budget needs; the White House said it would provide that.

Mulvaney said Trump was willing to forgo a concrete wall for steel or other materials.

The U.S. president's acting chief of staff Mick Mulvaney says he believes Democrats are dragging out the stalemate 'because they think it hurts the president.' (Mark Wilson/Getty Images)

"If he has to give up a concrete wall, replace it with a steel fence in order to do that so that Democrats can say, `See? He's not building a wall anymore,' that should help us move in the right direction," Mulvaney told NBC.

The president has suggested his definition of the wall is flexible, referring to slats and other "border things." Democrats have made clear they see a wall as immoral and ineffective and prefer other types of border security funded at already agreed upon levels.

Trump had campaigned on the promise that Mexico would pay for the wall. Mexico has refused. He's now demanding the money from Congress.