An international coalition of disarmament and human rights groups has said that UN-sponsored talks in Geneva this week must seize the opportunity to ban the development of fully autonomous weapons, dubbed "killer robots".

The Campaign to Stop Killer Robots said that such weapons, once activated, would select and engage targets without human intervention.

Though they have yet to be fully developed, robotic systems with various degrees of autonomy and lethality are used by the US, Israel, South Korea, and the UK, while other nations, including China and Russia, are believed to be moving toward systems that would give full combat autonomy to machines, the campaign warned.

"In recent months, fully autonomous weapons have gone from an obscure, little-known issue, to one that is commanding international attention", it said.

The Geneva meeting is expected to lead to an agreement to place the issue of "killer robots" firmly on the agenda of the UN Convention on Conventional Weapons. "Most fundamentally, an international ban is needed to ensure that humans will retain control over decisions to target and use force against other humans," said Mary Wareham of Human Rights Watch (HRW).

The US defence department issued a directive on 21 November 2012 that requires a human being to be "in the loop" when decisions are made about using lethal force, unless department officials waive the policy at a high level, HRW said.

However, it added that the directive was not a comprehensive or permanent solution to the potential problems posed by fully autonomous systems. "The policy of self-restraint it embraces may also be hard to sustain if other nations begin to deploy fully autonomous weapons systems", it added.

"Governments must address the fundamental question of whether it is inherently wrong to let autonomous machines make programmed decisions about who and when to kill," said Professor Noel Sharkey, chair of the International Committee for Robot Arms Control (ICRAC),

Thomas Nash, director of Article 36, set up to prevent the unintended, unnecessary or unacceptable harm caused by certain weapons, said: "The UK is in a strong position to play a leadership role in developing such a treaty. This country has advanced scientific and military capabilities, diplomatic clout around the world and a policy position that says weapons should always be under human control".

Nash added: "The problem is the government seems to be saying we don't need new international rules to govern these unprecedented technological developments around autonomy on the battlefield. That position is at best naive and at worst reckless."

The campaign to stop autonomous weapons is an international coalition of civil society groups. It says a ban "should be achieved through an international treaty, as well as through national laws and other measures, to enshrine the principle that decisions to use violent force against a human being must always be made by a human being".