WASHINGTON - (AP) - The Pentagon is about to pull its attack planes out of the international air campaign in Libya, hoping NATO partners can take up the slack.

The announcement Thursday drew incredulous reactions from somein Congress who wondered aloud why the Obama administration wouldbow out of a key element of the strategy for protecting Libyancivilians and crippling Moammar Gadhafi's army.

"Odd," "troubling" and "unnerving" were among criticalcomments by senators pressing for an explanation of theannouncement by Defense Secretary Robert Gates and Joint Chiefschairman Adm. Mike Mullen that American combat missions will endSaturday.

"Your timing is exquisite," Republican Sen. John McCain saidsarcastically, alluding to Gadhafi's military advances this week.

Gates and Mullen, in back-to-back appearances before the Houseof Representatives and Senate armed services committees, alsoforcefully argued against putting the U.S. in the role of arming ortraining Libyan rebel forces, while suggesting it might be a jobfor Arab or other countries. The White House has said repeatedlythat it has not ruled out arming the rebels, who have retreatedpell-mell this week under the pressure of a renewed easternoffensive by Gadhafi's better-armed and better-trained groundtroops.

Gates said no one should be surprised by the U.S. combat airpullback, but he called the timing "unfortunate" in light ofGadhafi's battlefield gains. He noted that the air attacks are acentral feature of the overall military strategy; over time theycould degrade Gadhafi's firepower to a point that he would beunable to put down a renewed uprising by opposition forces, hesaid.