Treasury Secretary Jack Lew said Tuesday that President Obama will not negotiate with House Republicans on the debt limit.

Lew said Obama will only accept a clean debt limit increase and won't entertain the idea of spending cuts equal to the debt limit increase, as House Speaker John Boehner (R-Ohio) has demanded -- or anything else.

"The president has been very clear: We are not going to be negotiating over the debt limit," Lew said on CNBC. "Congress has already authorized funding, committed us to make expenditures. We are now in the place where the only question is, will we pay the bills the United States has incurred?"

Asked whether Obama would accept anything tacked on to the debt limit, Lew said he would not.

"I will reiterate: The president made clear he is not negotiating over the debt limit," Lew said.

Lew said that the economy needs some certainty and that Republicans could provide that by agreeing to a clean debt limit increase without drawing out the process close to the mid-October deadline.

Lew on Monday formally informed congressional leaders that the United States will run out of borrowing authority in mid-October.