WASHINGTON — The Senate adjourned on Saturday with Democrats and the White House still far from striking a deal to reopen the government. The move meant that the partial government shutdown that began just after midnight Saturday was likely to continue well into next week.

Senate leaders announced that the chamber would meet next for a pro forma session Monday, but would not actually convene again in a scheduled session until Thursday, Dec. 27.

Sen. David Perdue, R-Ga., a key figure in the president’s corner in this fight, told NBC News that Vice President Mike Pence came to Senate Minority Leader Chuck Schumer, D-N.Y., today with a presidential request that fell between the $1.6 billion initially negotiated in Congress weeks ago for a border wall, and the $5 billion figure passed by the House but rejected by the Senate this week.

“The vice president came in for a discussion and made an offer. Unfortunately, we’re still very far apart,” a Schumer spokesperson told reporters.

After lunch with conservative lawmakers at the White House Saturday, President Donald Trump is prepared for a longer fight, Sen. Lindsey Graham, R-S.C., who attended the lunch, told NBC.

“We came out of the lunch with a commitment from the president that we’re going to get more than $1.6 billion for the wall,” Graham said.

On the Hill, lawmakers in both parties said much of the confusion at this point is how money is directed, and what exactly constitutes an acceptable wall, fence or barrier — a key political point for Democrats who won’t support a “wall,” and Republicans who demand one.

“To me it doesn’t matter what we want, let’s have a design that works,” Sen. James Lankford, R-Okla., told NBC. “The president put out a tweet of a picture with spikes on top of fencing, that’s not even in the conversation. That’s not even in one of the designs the border patrol has proposed.”

The White House continued to signal it was open to a more expansive definition. When asked if Trump is demanding funding for a concrete wall as part of the deal to end the shutdown, a senior administration official told reporters Saturday he was not: “He wants $5 billion in physical barrier... He is not insisting on this being a concrete barrier.”

A Senate Democratic aide said the House and Senate leadership of both parties — as well as the president himself — would all need to sign off on any deal before it went up for a vote.

Senate Majority Leader Mitch McConnell, R-Ky., in closing remarks on the Senate floor Saturday, said "productive discussions are continuing."

"When those negotiations produce a solution that is acceptable to all parties — which means 60 votes in the Senate, a majority in the House, and a presidential signature — at that point, we will take it up here on the Senate floor,” he said.

Trump, who put on hold a scheduled holiday trip to his Florida resort Mar-a-Lago Friday, tweeted Saturday morning that he was "in the White House, working hard." Later Saturday, the White House said first lady Melania Trump would return from Florida so the couple could spend Christmas together.

"We are negotiating with the Democrats on desperately needed Border Security (Gangs, Drugs, Human Trafficking & more) but it could be a long stay," he said, before meeting with top advisers and GOP lawmakers.

It remained unclear exactly how long the shutdown would last: days, weeks, or even into early January, when Democrats will retake the House majority.

This marks the third shutdown of the year and of the Trump administration. The first, in January, lasted 69 hours. The second, which occurred in February, lasted 9 hours.

Under the current partial shutdown, more than 420,000 federal employees will be required to work without pay and an additional 380,000 will be sent home, according to a fact sheet compiled by Senate Democrats. TSA employees, correctional officers, FBI agents, U.S. Marshals, Border Patrol officers, Coast Guard employees, Forest Service firefighters and Weather Service forecasters are all expected to continue working without pay, though they may be reimbursed later.