Aerial reconnaissance and attack drones have had a liberating effect on U.S. military forces, but they are deeply hated by many people and their overuse could jeopardize Washington's broader objectives, retired General Stanley McChrystal said on Monday.

McChrystal, who authored the U.S. counterinsurgency strategy in Afghanistan, said use of drones had enabled him to carry out missions with smaller groups of special operations forces because the "eye in the sky" provided backup security.

"What scares me about drone strikes is how they are perceived around the world," he said in an interview. "The resentment created by American use of unmanned strikes ... is much greater than the average American appreciates. They are hated on a visceral level, even by people who've never seen one or seen the effects of one."

McChrystal said the use of drones exacerbates a "perception of American arrogance that says, 'Well we can fly where we want, we can shoot where we want, because we can.'"

Drones should be used in the context of an overall strategy, he said, and if their use threatens the broader goals or creates more problems than it solves, then you have to ask whether they are the right tool.

President Barack Obama's heavy reliance on drones to wage war against al Qaeda in Afghanistan, Pakistan and elsewhere has provoked questions about the use of the aircraft and the legality of targeted killings.

Washington has not been swayed by the criticism and Obama nominated the official behind the campaign, top counterterrorism adviser John Brennan, to be the next CIA director....