WASHINGTON—U.S. House Majority Leader Eric Cantor (R., Va.) sounded a tough note on the nation's borrowing limit, saying Republicans wouldn't agree to raise the debt ceiling without assurances of cuts in government spending.

"We are simply not going to accept an increase in the debt limit without serious cuts and reforms," Mr. Cantor told reporters Tuesday. "If our votes are needed, which I assume the president thinks they are, then we will be acting to ensure the people that elected us that Washington's spending binge is over."

Other House Republican leaders have said that the debt limit will have to be raised, with House Budget Committee Chairman Paul Ryan (R., Wis.) saying recently that he didn't want the U.S. to default on its obligations. But Mr. Cantor declined to make similar assertions, saying that he was "not going to opine one way or the other" about whether Republicans would vote against raising the nation's borrowing limit.

That partly reflects the challenge that Republican leaders may face in keeping their caucus together in negotiations with the White House. Many tea party-backed Republicans have said they will vote against increasing the nation's borrowing capacity, even though failure to do so could cause the federal government to gradually start to shut down or possibly cause the U.S. to default on its sovereign-debt obligations.

In typical times, Congress raises the debt limit automatically, as part of the budget process. But things became more politically thorny after the U.S. economy hit tough times, lowering tax receipts and prompting the government to increase spending to blunt the effects of high unemployment.

House Republicans, who took over the chamber this month vowing to rein in budget deficits, have said they will require lawmakers to go on record in favor of an unpopular borrowing increase, or to vote 'no' and risk putting the country into default.

Earlier this month, U.S. Treasury Secretary Timothy Geithner told Congress that the U.S. could reach its $14.3 trillion borrowing limit as soon as March 31. In a letter to lawmakers, Mr. Geithner said that failure to act could "precipitate a default by the United States." He said that the U.S. had about $335 billion of borrowing capacity left before it reached the limit.

"It's a serious vote and has serious consequences on both sides of the vote," Mr. Cantor said. "What we need to do and are committed to doing is making sure that we achieve spending cuts and effect real reforms so that the spending binge ends. We look at the debt limit vote as an opportunity for us to accomplish those goals."

Asked whether he agreed that the U.S. would reach its borrowing limit as soon as March 31, Mr. Cantor said that "we are looking into exactly what is available for the Treasury Department to continue to operate." He said that "obviously we will be in discussions with the administration as far as the time sense and the urgency of that vote."

Write to Siobhan Hughes at siobhan.hughes@dowjones.com