WASHINGTON (AP) — House Speaker John Boehner promised Thursday that the GOP-controlled House won't miss a late-February deadline to increase the government's borrowing cap.

"Look, we do not want to default on our debt, and we're not going to default on our debt," Boehner said.

The Ohio Republican held open the possibility that the House could consider a debt limit increase that's "clean" of any GOP add-ons.

Boehner is struggling to win enough support among Republicans to pass a debt limit measure without help from Democrats. He has already discarded adding provisions to the must-pass measure such as a mandate that the Obama administration approve the Keystone XL pipeline.

The government reaches its borrowing limit on Friday, and Treasury Secretary Jacob Lew is employing bookkeeping maneuvers to buy a few weeks' time for Congress to act. Lifting the cap on the government's more than $17 trillion debt is needed to permit the government to meet all of its obligations, including Social Security benefits, interest payments on U.S. treasuries, federal workers' salaries and payments to federal contractors. Failing to do so would be unprecedented and, experts warn, could roil financial markets and the economy.

President Barack Obama has said he won't permit Republicans to use the debt limit as a vehicle for GOP priorities. Two debt limit increases were enacted last year that included only modest add-ons, such as a provision forcing Senate Democrats to pass a budget.

"It's the responsibility of Congress to ensure that bills that have already been incurred are paid in a timely fashion, so that the United States doesn't default," White House Press Secretary Jay Carney said on Thursday. "We are not going to pay ransom in return for Congress fulfilling this basic responsibility."

Boehner is tempering expectations that the GOP might be able to extract much in exchange for an increase in the government's borrowing cap — and he doesn't sound optimistic he can accomplish it without help from Democrats.

"Mother Theresa is a saint now, but if the Congress wanted to make her a saint and attach that to the debt ceiling, we probably couldn't get 218 Republican votes," the speaker said.