Washington: Lockheed Martin's precision-strike missile, the Hellfire, is set for an upgrade that will make it even deadlier in performance. The Hellfire is the missile that rains down on al Qaeda and allied militants in Afghanistan, Yemen, Somalia and the tribal areas of Pakistan, fired from unmanned drones, such as Predators, and helicopters.

The cylindrical, 108-pound (49-kg) missile, known as Hellfire II, is the principal weapon used by unmanned, remotely piloted aircraft, such as General Atomics MQ-1A Predator and the MQ-9 Reaper.

The upgraded Hellfire or the Hellfire Romeo will now encapsulate all the killer applications of the previous Hellfire II model into a single warhead and provide greater operational flexibility to users, according to Lockheed Martin Corp.

The manufacturer describes the upgraded version as "One missile for many missions."

The new missile is designated the AGM-114R, or Hellfire Romeo.

Tipped with a "multi-purpose" warhead it is designed to knock out "hard, soft and enclosed targets" with a single Hellfire missile load, says Lockheed.

Lockheed said in March that the new version would enter service late next year. Testing is currently underway.

The "R" version's warhead combines the shaped-charge anti-armour capability of the initial anti-tank version with the enhanced effects of fragmentation, blast/fragmentation and heat/blast/overpressure built into later models allowing it to be used against a far greater range of targets.

Experts point out that earlier one would have to employ a specific missile-type to attack a particular kind of target -- tank, truck or foot soldier. Equipped with the Romeo, an aircraft would engage 'targets of opportunity' as they appear on the battlefield.

Also, for the first time, the new version will be capable of being launched against "off-bore" targets, meaning the aircraft or helicopter need not be pointing at the target to acquire it.

Hellfire, a loose acronym for Heliborne, Laser, Fire and Forget, is the primary air-to-ground missile system for the US armed forces and other intelligence and paramilitary organisations and allied nations.

The new missile, like its predecessors, can be launched from a range of platforms in the air, at sea or on the ground. It will use a designator spot laser that can lock on to its target before or after launch.

The air-launched Hellfire missiles have been exported to a large number of countries around the world.