"Once developed, lethal autonomous weapons will permit armed conflict to be fought at a scale greater than ever, and at timescales 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.
"We do not have long to act. Once this Pandora's box is opened, it will be hard to close."
Walsh has previously travelled to speak in front of the United Nations in an effort to have the international body prevent the proliferation of killer robots. Speaking to news.com.au in February he said "the arms race is already starting."
He believes it's a matter of years not decades until military weapons are imbued with some level of autonomy - which poses a number of worrying scenarios, particularly if they fall into the wrong hands.
"They get in the hands of the wrong people and they can be turned against us. They can be used by terrorist organisations," he warned.
"It would be a terrifying future if we allow ourselves to go down this road."
There are immense positives to the development of artificial intelligence and the technology is set to permeate untold facets of our lives. It is expected to be used to tackle social problems like inequality, poverty and help address the challenges posed by climate change.
"However, the same technology can also be used in autonomous weapons to industrialise war," Walsh said.
"We need to make decisions today choosing which of these futures we want. I strongly support the call by many humanitarian and other organisations for an UN ban on such weapons, similar to bans on chemical and other weapons," he said in a statement alongside the letter.
Ryan Gariepy is the founder and chief technology officer of Clearpath Robotics in Canada and was the first to sign the letter.
"We should not lose sight of the fact that, unlike other potential manifestations of AI which still remain in the realm of science fiction, autonomous weapons systems are on the cusp of development right now and have a very real potential to cause significant harm to innocent people along with global instability," he said.
"The development of lethal autonomous weapons systems is unwise, unethical and should be banned on an international scale."
In 2015 Walsh spearheaded a similar letter calling for collective action to curb autonomous weapons which was signed by, among others, Apple co-founder Steve Wozniak and world renowned physicist Stephen Hawking.
Walsh said the initial letter "helped push this issue up the agenda" at the United Nations and begin formal talks.
In December 2016, 123 member nations of the United Nation's Review Conference of the Convention on Conventional Weapons unanimously agreed to begin formal discussions on autonomous weapons. Of these member, 19 have already called for an outright ban.
"I am hopeful that this new letter, adding the support of the AI and robotics industry, will add urgency to the discussions at the UN that should have started today," Walsh said.
