Autonomous "killer robots" are a real possibility and must be banned before governments start deploying them, campaigners have warned.

The report 'Losing Humanity' - issued by Human Rights Watch (HRW) and Harvard Law School's International Human Rights Clinic - raised the alarm over the ethics of the looming technology.

Calling them "killer robots," the report urged "an international treaty that would absolutely prohibit the development, production, and use of fully autonomous weapons".

The US military already leads the way in military robots, notably the unmanned aircraft or drones used for surveillance or attacks over Pakistan, Afghanistan, Yemen and elsewhere.

But these are controlled by human operators in ground bases and are not able to kill without authorisation.

Fully autonomous robots that decide for themselves when to fire could be developed within 20 to 30 years, or "even sooner," the 50-page report said, adding that weapon systems that require little human intervention already exist.

Perhaps closest to the Terminator-type killing machine portrayed in Arnold Schwarzenegger's action films is a Samsung sentry robot already being used in South Korea, with the ability to spot unusual activity, talk to intruders and, when authorised by a human controller, shoot them.

Fully autonomous fighting machines would spare human troops from dangerous situations.

The downside, though, is that robots would then be left to make nuanced decisions on their own, the most fraught being the need to distinguish between civilians and combatants in a war zone.

"A number of governments, including the United States, are very excited about moving in this direction, very excited about taking the soldier off the battlefield and putting machines on the battlefield and thereby lowering casualties," said Steve Goose, arms division director at HRW.

While Mr Goose said "killer robots" do not exist as yet, he warned of precursors.

He added the best way to forestall an ethical nightmare is a "pre-emptive, comprehensive prohibition on the development or production of these systems."

AFP