U.S. President Barack Obama has approved the use of armed Predator drones in Libya, Defense Secretary Robert Gates said Thursday.

Gates told CNN the unmanned Predators would allow for "some precision capability" against the forces of longtime Libyan leader Moammar Gadhafi, and will offer a "modest contribution" to NATO efforts to support Libyan rebels.

NATO, meanwhile, has signaled it may ramp up air strikes on Gadhafi's regime. NATO issued a new warning to Libyan civilians to stay away from military areas - foreshadowing plans for attacks on targets seen as strategically significant in stopping the government's attacks against civilians, according to a NATO military official.

Libyan rebels had recently complained that NATO was not being aggressive enough to protect civilians from Gadhafi's forces.

Planes and missiles from a coalition including the United States, the United Kingdom and France began attacking Libyan air-defense targets March 19 in part to establish a no-fly zone. It was authorized by a U.N. Security Council resolution, which approved military action –short of occupation - to prevent Gadhafi's forces from attacking civilians and cities.

The intervention came after a Libyan uprising, which began in mid-February after clashes between government forces and protesters. Opposition forces are seeking the ouster of Gadhafi, who has ruled for nearly 42 years.