The first leg of Gen. David Petraeus’ confirmation hearing to be the next top U.S. military commander in Afghanistan concluded with a testy exchange with Sen. Lindsey Graham.

The South Carolina Republican pressed Petraeus on President Barack Obama’s plan to begin withdrawing troops from Afghanistan beginning in July 2011. In testimony before the Senate Armed Services Committee, Petraeus attempted to walk a fine line between supporting White House policy and assuring concerned Senators that the U.S. will not withdraw from the region without accomplishing the mission.

“Somebody needs to get it straight … what the hell we’re going to do come July 2011,” Graham said, upon questioning Petraeus.

“Let’s think about it from the enemy’s perspective and perspective of our friends,” responded Petraeus, head of U.S. Central Command. “They should be assured that we’re going to pursue the enemy relentlessly.”

In a brief interview following the exchange, Graham said he remains confused over the Obama administration’s plan to withdraw troops. Graham said he would still like to know if troops will begin withdrawing in July 2011 no matter what, or whether the exit will be conditions based.

The Armed Services Committee is expected to act quickly on Petraeus’ nomination. He was tapped by Obama last week to replace embattled Gen. Stanley McChrystal, who was forced from the post after he and his staff made disparaging remarks about the administration in a Rolling Stone article.