A rebel fighter walks at a war-damaged crossroad in Tripoli street in central Misrata April 21, 2011. [Photo/Agencies]

WASHINGTON - US Defense Secretary Robert Gates on Thursday said President Barack Obama has approved the use of armed Predator drones in the military mission in Libya, and the unmanned aerial vehicles can provide unique capabilities to the NATO forces operating in the Northern African country.

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Gates said the drones were introduced because of "humanitarian situation" in Libya, and the drones have "capability that even the A10 and AC130 couldn't provide." A10 and AC130 were ground attacking planes introduced earlier that could decimate tanks and troops.

Vice Chairman of the Joint Chiefs of Staff James Cartwright, who briefed reporters together with Gates, said Predator drones' ability to get lower than regular fighter jets allows the coalition to conduct low-level precision attacks on Libyan government forces.

He said the remote-controlled drones can provide better vision of the battleground, and manage collateral damage better. Their ability for "extended persistence" in targets, which means they can fly much longer periods of time than regular planes in the sky, brings capability to the conflict that NATO partners don't have.

Predator drones and can fly surveillance missions and fire Hellfire missiles. They were used extensively in Afghanistan, but Gates said the drones used in Libya did not come from Afghanistan.

They also claimed the use of Predator drones isn't "mission creep," which means the expansion of a mission beyond its original goals.

Although the United States has handed over command of the Libyan mission to NATO, it still provides some of the most critical capabilities in the conflict, such as aerial refueling, jamming, surveillance and certain ground attack capabilities.