The Republican-controlled House has backed away from a battle over the government's debt cap and passed a measure extending Treasury's borrowing authority with overwhelming support from U.S. President Barack Obama's Democratic allies.

The 221-201 vote came hours after Speaker John Boehner announced that his fractured party would relent and not seek to add other items to the must-pass legislation.

Twenty-eight Republicans voted yes. The bill would permit Treasury to borrow normally for another 13 months and would diffuse the chance of a debt crisis well past the November elections.

"We'll let his party give him the debt ceiling increase that he wants," Boehner said, hours before the evening vote.

Boehner announced the plan after a poll of Republican members found insufficient support for a strategy that would have made passage of the debt limit increase conditional on a plan to reverse a recently passed cut to military pensions. Obama and congressional Democrats argued the Republicans should not try to use a vote on the debt limit to extract concessions from the administration.

"We'll let the Democrats put the votes up," the speaker had said. "We'll put a minimum number of  votes up to get it passed."

He said he had expected almost all of Obama's Democratic allies to vote for the so-called clean debt cap increase but he would be one of the few Republicans to back it as well. The vote is scheduled for Tuesday evening.

Boehner's announcement came after a plan hatched on Monday to reverse the cut in military pensions as the price for increasing the government's borrowing cap got a rocky reception from skeptical conservatives.

Had thought to tie vote to Keystone

Republican leaders had earlier attempted to build support for plans to tie a debt cap increase to approval of the Keystone XL pipeline or repeal of part of the new health care law; both those efforts fell flat as well. He said his inability to assemble 218 GOP votes — enough to win a floor vote — for any debt limit plan left him no alternative but to turn to Democrats.

"When you don't have 218 votes, you have nothing. We've seen that before and we see it again," Boehner said, adding that House Minority Leader Nancy Pelosi, D-Calif., promised him sweeping Democratic support in Wednesday's vote. More than 180 Democrats have signed a letter pledging to vote for a clean increase in the debt cap.

The White House applauded the move. Gene Sperling, director of the White House's National Economic Council, said the administration hopes Tuesday's development means "that the tactic of threatening default or threatening the full faith and credit of the United States for budget debates is over, off the table and never is going to happen again. And if so that would, I think, be a boost for confidence and investment in the US."

"That's how it's supposed to work," said Vice President Joe Biden at the Capitol after swearing in the newest senator, John Walsh, D-Mont.

The announcement amounted to a bitter defeat for a party that has sought to use must-pass debt ceiling measures as leverage to force spending cuts on Democrats. Republicans won more than $2 trillion in spending cuts in a 2011 showdown, but gave Obama two debt limit increases last year with only modest add-ons.