Tesla chief Elon Musk and Mustafa Suleyman, the co-founder of Google's DeepMind, are among more than 100 experts in artificial intelligence who are urging the United Nations to ban lethal autonomous weapons, known as “killer robots.”

In an open letter to the International Joint Conference on Artificial Intelligence, the tech experts say lethal autonomous weapons “threaten to become the third revolution in warfare,” but one that few would be able to control.

Like autonomous cars, autonomous weapons are still not fully developed, but several semi-autonomous weapons, such as drones and self-driving tanks, already exist. Fully autonomous weapons are designed to operate on their own, selecting and attacking military targets without humans operating them remotely.

While some contend the weapons would make battle safer for military personnel, the 116 tech experts signing the open letter worry the weapons would simply make it easier to go into battle.

"Once developed, they will permit armed conflict to be fought at a scale greater than ever and, at times, scales faster than humans can comprehend.

"These can be weapons of terror, weapons that despots and terrorists use against innocent populations, and weapons hacked to behave in undesirable ways," reads their letter.

The signatories want “killer robots” to be added to the list of weapons banned under the UN’s Convention on Certain Conventional Weapons, which already includes landmines, chemical weapons and blinding laser weapons.

Signatories to the letter say with killer robot technology advancing quickly, the need to impose a ban is urgent.

"We do not have long to act. Once this Pandora's box is opened, it will be hard to close," they write.

The letter was released to coincide with Monday’s planned meeting of the International Joint Conference on Artificial Intelligence, but the meeting was cancelled and postponed until November, because of disputes over due payments.