Washington CNN  — 

Progress in talks to reopen the government remains at a standstill after Saturday’s meeting with Trump administration officials and congressional staff, acting White House chief of staff Mick Mulvaney said Saturday.

Mulvaney told CNN’s Jake Tapper that they “did not make much progress” at the meeting, adding that he thought Democrats were “actually, in my mind, there to stall.”

“We didn’t make much progress at the meeting, which was surprising to me,” Mulvaney said. “I thought we had come in to talk about terms that we could agree on, places where we all agreed we should be spending more time, more attention, things we could do to improve our border security. And yet the opening line from one of the lead Democrat negotiators was that they were not there to talk about any agreement.”

President Donald Trump also said in a tweet Saturday afternoon that the meeting didn’t make “much headway.”

“V.P. Mike Pence and team just left the White House,” Trump wrote. “Briefed me on their meeting with the Schumer/Pelosi representatives. Not much headway made today. Second meeting set for tomorrow. After so many decades, must finally and permanently fix the problems on the Southern Border!”

Members of the Trump administration and congressional leaders have met several times since the government partially shut down two weeks ago, but prospects of the government opening anytime soon seem bleak as both sides appear reluctant to budge on funding for border security and a wall.

A source in Saturday’s meeting said “baby steps” were made, but Democrats are asking for an official justification from the Trump administration of the demand for $5.6 billion in wall funding and border security.

The administration will produce that justification Saturday night or Sunday in an attempt to further talks by Sunday afternoon.

A second source familiar with the meeting said Democratic aides made clear that they “need” the government open, and then they will continue to negotiate border security.

Democratic staff in the room also said it will grow increasingly hard to start formal negotiations with parts of the government closed, a Democratic source familiar with the discussion said. But administration officials rejected the demand, the source said.

“It will be difficult to make real progress as long as the President keeps the government closed,” a Democratic aide briefed on the meeting said.

Democrats want an updated budget request because the last one is a year old and asked for only $1.6 billion. They want to see what the Department of Homeland Security would be willing to cut to make the request work from a budgetary standpoint.

A House GOP leadership aide called Saturday’s discussion “productive,” adding that it was “beneficial” to have Homeland Security Secretary Kirstjen Nielsen “finally be able to outline the crisis at the border in detail without interruption, given her prior efforts were cut off by Democrat leaders.”

An aide to the vice president said the participants in the meeting did not discuss a dollar figure in any depth, but talked about priorities for border security.

The group agreed to meet again on Sunday, the House GOP leadership aide said.

Another Republican leadership aide said Sunday’s meeting would focus on a budget sheet justification, re-outlining what the administration says it needs to secure the border.

However, a Democratic source familiar with Saturday’s discussion said the vice president made it clear that the White House will not move off of the $5.6 billion proposal.

On Friday, Trump told members of Congress he had no plans to move on from his demand for $5.6 billion to build a border wall, according to a person familiar with the meeting.

Mulvaney on Saturday reiterated that Trump’s demand for funding for a border wall has not changed.

“I think the President has said for a long time that it’s 5.6 billion for border security, including the wall,” Mulvaney said. “We recognize that things like technology are important, border crossings are important, but certainly a barrier is important.”

Trump said during the meeting Friday that he was prepared to keep the government closed for an extended period of time, according to Senate Minority Leader Chuck Schumer, who told reporters that Trump said “he’d keep the government closed for a very long period of time – months or even years.”

“Absolutely I said that,” Trump confirmed from the Rose Garden after the meeting. “I don’t think it will, but I’m prepared.”

House Speaker Nancy Pelosi said in a statement Saturday afternoon that the House will begin passing individual spending bills next week to reopen parts of the government, beginning with legislation to fund the Treasury Department and the IRS in order to process Americans’ tax refunds on time. But there is no indication the Senate will take up the measures or that the White House would support them since it threatened earlier this week to veto a bill to fund all of the closed departments except Homeland Security.

Trump continued to attack Democrats on Saturday morning in a series of tweets.

“The Democrats could solve the Shutdown problem in a very short period of time,” he wrote. “All they have to do is approve REAL Border Security (including a Wall), something which everyone, other than drug dealers, human traffickers and criminals, want very badly! This would be so easy to do!”

CNN’s Dana Bash, Jim Acosta, Ashley Killough, Phil Mattingly and Caroline Kelly contributed to this report.