Congressional leaders reached an agreement Thursday to temporarily extend a payroll-tax cut by two months and begin negotiations on a yearlong extension, aides said.

The agreement could end a political stalemate over the payroll-tax cut, which lowered Social Security taxes for 160 million Americans in 2011. Under the tentative agreement, the House will vote again on a two-month extension and the Senate will prepare to negotiate for an extension that will run through 2012.