Democrats on Tuesday withdrew an offer to fund U.S. President Donald Trump’s border wall, as tough negotiations over the future of young illegal immigrants resumed in the Senate.

A day after the end of a government shutdown linked to wrangling over immigration, Senate Democratic Leader Chuck Schumer said he pulled the offer because of what he said was Trump’s failure to follow through on the outlines of an agreement the two men discussed last Friday.

“So we’re going to have to start on a new basis and the wall offer is off the table,” Schumer told reporters.

During the 2016 election campaign, Republican Trump said Mexico would pay the cost of building a wall along the southwestern border of the United States to keep out illegal immigrants. Mexico has rejected the idea.

As a result Trump has been forced to ask Congress for U.S. taxpayer funds for the wall; government estimates are that it could cost over $21 billion.

With Democrats and many Republicans arguing there are more effective border enforcement tools than a wall, the proposal has become a major sticking point in immigration negotiations, which in turn have complicated talks about funding federal agencies.

The Senate’s No. 2 Democrat, Dick Durbin, asked by a reporter whether Schumer offered Trump $25 billion for the wall in a major concession to the president, did not dispute the figure, but said: “He did it in the context of a negotiation.”

Democrats have been spearheading an effort to protect around 700,000 young, undocumented immigrants from deportation after Trump last September announced the end of the Deferred Action for Childhood Arrivals (DACA) program instituted by his predecessor, President Barack Obama, a Democrat.

The program, which began in 2012, gave qualified so-called Dreamers, immigrants who were brought illegally into the United States as children, temporary protection from deportation and the ability to study and work in the United States.

Sen. John Cornyn, the No. 2 Senate Republican, criticized Schumer for pulling the wall funding offer.

“That basically sets the DACA discussion back,” he told reporters.

Cornyn said there have been discussions of he and Durbin being a “clearinghouse” for suggestions from senators on legislation to rescue Dreamers from the threat of deportation and provide permanent protections for them.

In agreeing on Monday to end a three-day-old government shutdown and fund the government until Feb. 8, Senate Democrats got a promise from Senate Majority Leader Mitch McConnell that he would allow an immigration debate on the Senate floor in the near future, the first one since 2013.

Durbin said a similar commitment is now needed from Paul Ryan, the Republican speaker of the House of Representatives, where a Dreamer bill would presumably face a much harder path to passage than in the Senate.

The White House on Tuesday rejected the idea that a bipartisan bill sponsored by Durbin and Republican Sen. Lindsey Graham could be the core of a solution.

White House spokeswoman Sarah Sanders said the proposal was “totally unacceptable to the president and should be declared dead on arrival.”

Trump himself has vacillated on immigration between tough rhetoric demanding a U.S. border wall and a softer tone urging a “bill of love” for Dreamers.

“Nobody knows for sure that the Republicans & Democrats will be able to reach a deal on DACA by February 8, but everyone will be trying,” Trump wrote in a post on Twitter.