WASHINGTON — Treasury Secretary Steven Mnuchin told congressional leaders that the debt ceiling should be raised before lawmakers leave for their August recess to avert the potential of an unprecedented default on the national debt.

In a letter to House and Senate leaders Friday, Mnuchin said that based on updated projections, “there is a scenario in which we run out of cash in early September, before Congress reconvenes.”

The notification comes one day after House Speaker Nancy Pelosi said she wanted an agreement this month with President Donald Trump on raising the borrowing limit and setting spending levels for the coming budget year.

Pelosi’s office said that she and Mnuchin talked again by telephone on Friday and that negotiations would continue over the weekend.

The Bipartisan Policy Center, a centrist research organization, projected this week that lower-than-expected federal revenues this year could leave the government without the cash it needs in early September.