WASHINGTON  President Obama announced a tentative deal with Congressional Republicans on Monday to extend the Bush-era tax cuts at all income levels for two years as part of a package that would also keep benefits flowing to the long-term unemployed, cut payroll taxes for all workers for a year and take other steps to bolster the economy.

The deal appeared to resolve the first major standoff since the midterm elections between the White House and newly empowered Republicans on Capitol Hill. But it also highlighted the strains Mr. Obama faces in his own party as he navigates between a desire to get things done and a retreat from his own positions and the principles of many liberals.

Congressional Democrats pointedly noted that they had yet to agree to any deal, even as many Republicans signaled that they would go along.

Mr. Obama said that he did not like some elements of the framework, but that he had agreed to it to avoid having taxes increase for middle class Americans at the end of the year. He said that in return for agreeing to Republican demands that income tax rates not go up on upper-income brackets, he had secured substantial assistance to lower- and middle-income workers as well as the unemployed.