In a conference call for Democratic activists, they urged the activists to contact lawmakers to express opposition to a debt default that could be less than two weeks away.

Brainard, director of the White House National Economic Council, said Biden's negotiating team has been instructed to not agree to any proposal from Republicans on lifting the debt ceiling that would take healthcare away from Americans or push them into poverty.

Republicans who are threatening to let the government default on its debt are trying to persuade Democrats to accept tougher work requirements for some federal aid programs in exchange for lifting the borrowing cap.

"A debt default could trigger a recession," Harris said.

Brainard said the Biden administration's goal, in its talks with House of Representatives Speaker Kevin McCarthy's team, is to work toward a reasonable bipartisan budget agreement.

"The administration's negotiating team is fighting against extreme attempts to reverse the progress we've made: creating clean energy jobs, combating climate change and lowering costs for middle-class families, including for students and for insulin and other drugs," she said.