Efforts to resolve a government shutdown fight have been at a standstill since Saturday, when Democrats rejected a White House proposal that reduced President Trump's $5 billion demand for a border wall and offered flexibility on just how solid the wall needed to be.

According to a senior White House official, White House negotiators led by Vice President Mike Pence and White House senior adviser Jared Kushner huddled with Democrats on Capitol Hill Saturday and proposed between $1.6 billion and $5 billion in funds for a "physical barrier" that would include "fencing, a wall, and steel slats."

This, the official acknowledged, meant not all the funding would have to be used for a "wall."

[Read: 10 things to know about the government shutdown]

Democrats, led by Senate Minority Leader Chuck Schumer, D-N.Y., walked away and basically haven't been heard from since, according to the White House. "There's been dead silence," the senior official said. "Schumer and [House Minority Leader Nancy] Pelosi are meeting with themselves, refusing to meet with Republicans on the offer made last Saturday."

According to a House Democratic leadership aide, the offer the White House made was for $2.5 billion. Of the total, $2.1 billion would be used for what the aide termed "elements of border security," while $400 million would be devoted to what Democrats are calling a "slush fund" allocated to what they say are undefined "Trump immigration priorities." Schumer emphatically rejected the offer, the aide said.

In refusing to meet behind closed doors, Democrats are now insisting that any offer from the White House be made publicly by Trump. This, they claim, is because the numbers on the White House side keep changing, and the only way to nail down a proposal is for Trump to put it on the record.

“Sen. Schumer made clear to the vice president, in private after their Saturday meeting, that the offer would not pass the Senate, and told the vice president that we would not consider any offer the president has not publicly endorsed, given that the president has changed his position so many times," said a Schumer spokesman.

But the White House believes Democrats are simply stalling. Trump advisers claim Pelosi is trying to appease her base and secure her election as House speaker by refusing to negotiate on the wall.

A top Pelosi aide rejected the charge. "Leader Pelosi has been very clear in her opposition to the wall, for years," Pelosi deputy chief of staff Drew Hammill told the Washington Examiner. "There was a vote in the House in which Democrats were completely united. This should not be a surprise to the White House."