The US military plans to add a lethal new drone to its fleet -- a robotic helicopter for the US Navy equipped with laser-guided rockets, defense giant Northrop Grumman said Wednesday.

The armed Fire Scouts will mark a new era in naval warfare, offering an alternative to pilots flying attack helicopters or fighter jets off warships and reflecting a broader shift to robotic technology across the US military in recent years.

An unarmed version of the MQ-8B Fire Scout is already flying surveillance and reconnaissance missions for the US Navy, using cameras and sensors inside a cone on the aircraft's nose.

Northrop Grumman won a contract in September worth $17 million to outfit the choppers with 70 mm rockets, with racks capable of carrying eight or 14 of the weapons on an aircraft, the company said.

"The operational system will be delivered by 2013," company spokesman Warren Comer told AFP.

The Fire Scout joins two other armed drones in the US arsenal, the Predator and the Reaper, which are unmanned planes that have become the weapon of choice in covert CIA strikes against suspected Al-Qaeda militants and their associates in Pakistan and elsewhere.

"By arming the Fire Scout, the Navy will have a system that can locate and prosecute targets of interest. This capability shortens the kill chain and lessens the need to put our soldiers in harm's way," George Vardoulakis, Northrop's vice president for tactical unmanned systems, said in a statement.

The Fire Scout, which had its first test flight in 2000 and first landed on a naval ship at sea in 2006, is due to be deployed on new littoral combat ships under construction.

The helicopter, which is seven meters (23 feet) long and three meters (about 10 feet) high, can reach an altitude of 20,000 feet (6,000 meters), fly at a speed of more than 115 knots (200 kilometers) per hour and stay in the air for more than eight hours, employing sensors and radar to track targets.

The US Navy has a fleet of about 15 Fire Scouts and plans to build 168 of the helicopters, according to the Pentagon.

The Fire Scout has been deployed to Afghanistan to help target insurgents and one of the unmanned helicopters went down in the NATO-led air campaign over Libya in June.

Last year, US commanders in Washington considered shooting down an unarmed Fire Scout when it strayed off course and flew toward the US capital after losing ground communications.