Treasury Secretary Janet Yellen affirmed on Monday that the nation faces federal default as soon as June 1, dialing up pressure on Congress to strike a deal. 

In her previous letter to lawmakers earlier this month, Yellen warned that the Treasury could run out of cash to stave off a federal default by early June if Congress did not raise or suspend the debt ceiling.

“We still estimate that Treasury will likely no longer be able to satisfy all of the government’s obligations if Congress has not acted to raise or suspend the debt limit by early June, and potentially as early as June 1,” Yellen wrote to leaders Monday.

Yellen said she plans to provide additional updates to Congress in the weeks ahead, noting the actual date Treasury exhausts those measures “could be a number of days or weeks later than these estimates.”

Treasury began implementing the emergency measures in January, when the nation ran up on the roughly $31.4 trillion cap set by Congress more than a year ago. 

Yellen’s letter comes as White House and congressional leaders struggle to strike an agreement to raise the federal borrowing limit.

President Biden is expected to meet with Speaker Kevin McCarthy (R-Calif.) and other leaders on Tuesday, as both sides try to find a path forward on the debt limit after a months-long stalemate.

Republicans have vowed not to work with Democrats to raise the debt ceiling without cuts or fiscal reforms, while Democrats have instead called for a “clean” bill to address the debt ceiling, insisting bipartisan budget talks be carried out separately.  

In remarks to reporters earlier on Monday, McCarthy indicated both sides had not made much progress since talks began last week.

“I still think we’re far apart. It doesn’t seem to me yet they want a deal, it just seems like they want to look like they are in a meeting but they’re not taking anything serious,” McCarthy said, underlining the challenges both sides face in striking a deal soon. 

Updated at 5:05 p.m.