WASHINGTON — The Pentagon’s top civilian and military officials on Sunday expressed an expectation, even a desire, that American troops would remain in Afghanistan after the NATO mission ends in December 2014, although they emphasized that no decision had been made.

Defense Secretary Leon E. Panetta and Gen. Martin E. Dempsey, chairman of the Joint Chiefs of Staff, said the United States would sustain a strategic partnership with Afghanistan, and they cited a decision by the NATO heads of state during a summit meeting last year in President Obama’s hometown, Chicago, that long-term support for Kabul would include military assistance.

“In Chicago, we also said that we’re committing to an enduring presence,” Mr. Panetta said. “And I believe that the president of the United States is going to do everything possible to implement the Chicago agreements.”

During joint appearances on the NBC News program “Meet the Press” and the CNN program “State of the Union,” Mr. Panetta and General Dempsey sought to define and defend an 11-year-old mission in Afghanistan whose objectives have become fuzzy in the minds of many Americans. Mr. Obama is weighing how rapidly to withdraw the remaining troops and considering how many to propose leaving there after 2014.