Washington — President Obama went on the offensive today, telling student-loan companies that he was prepared to fight them over his plan to end bank-based lending.

Lenders “have mobilized an army of lobbyists,” he said in a speech that was introduced by Stephanie Stevenson, a financially struggling college student. “They are gearing up for battle. … So am I.”

“And for those who care about our future,” he added, “this is a battle we can’t lose.”

Calling government subsidies to lenders “wasteful and inefficient,” Mr. Obama argued that taxpayers’ money should be spent on students, not special interests.

“It’s about whether we want to give tens of billions of tax dollars to special interests or whether we want to make college more affordable for eight and a half million more students,” he said. “I think most of us would agree on what the right answer is.”

His remarks came as Congress put the finishing touches on a compromise budget blueprint that could ease passage of the president’s plan — or complicate it. If negotiators agree to the House of Representatives’ version of the measure, and include budget-cutting “reconciliation” instructions to the education committee, the plan could sail through Congress. If they don’t, it will need greater support to pass and could face a filibuster in the Senate.

Congress could vote on the budget as early as next week.

Student-loan companies wasted no time in responding to the president, issuing press releases even before Mr. Obama gave his speech. In one, Kevin Bruns, executive director of America’s Student Loan Providers, argued that ending bank-based lending would “do more harm than good” and would do “nothing to make college more affordable for the vast majority of students who require loans to pay for college.”

“What is the rush?,” he asked. “Why the haste to eliminate a succesful program?”

Lenders have been urging Congress to consider alternatives to the president’s plan and are pushing counterproposals with members of Congress. —Kelly Field