As talks had resumed Sunday to negotiate an end to the partial U.S. government shutdown that has thrown the livelihood and services of some 800,000 federal workers into uncertainty, President Donald Trump said that a "productive meeting" yielded plans for a steel wall along the U.S.-Mexico border.

"We are now planning a Steel Barrier rather than concrete," said Trump over Twitter Sunday. "It is both stronger & less obtrusive. Good solution, and made in the U.S.A."

Earlier in the day, Trump had also repeated his threats that he could declare a national emergency to get funding for a wall -- the sticking point of the ongoing budget negotiations.

"I may declare a national emergency dependent on what's going to happen over the next few days," Trump reportedly said on Sunday, after making similar threats in the past few days in televised press briefings -- and claiming that the partial U.S. government shutdown could last months or over a year.

London Bureau Chief Martin Baccardax discussed the shutdown on TheStreet's Trading Strategies podcast.

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Trump's statements come as Vice President Mike Pence hosted a meeting between congressional aides and Trump administration officials over the weekend -- with low expectations of resolving the budget bill and wall funding. 

"V.P. Mike Pence and group had a productive meeting with the Schumer/Pelosi representatives today," claimed Trump over Twitter after the meeting Sunday.

The weekend meetings -- which included Secretary of Homeland Security Kirstjen Nielsen and Presidential Adviser Jared Kushner -- came as Democratic lawmakers and Trump argue over a budget bill that has stalled over the president's demand that $5.6 billion be included to fund a border wall between the U.S. and Mexico. During the 2016 election, building the wall on Mexico's dime was Trump's central campaign promise. 

Democratic leadership has balked at the idea of funding the wall, but has offered money for other border security measures.

After Trump waved the idea of declaring a national emergency to build the wall, Democrats said they would respond with legal challenges.

"He'll face a challenge, I'm sure," U.S. Sen. Dick Durbin of Illinois said on CBS' "Face The Nation" on Sunday.

House Speaker Nancy Pelosi, a Democrat of California, meanwhile promised over the weekend that House Democrats would begin passing individual appropriations bills to re-open government agencies.