When Tesla (TSLA) - Get Report CEO Elon Musk shot back at Facebook (FB) - Get Report founder Mark Zuckerberg's claims that those warning against artificial intelligence were "irresponsible," he was just getting started.

Earlier this month, Musk sent several tweets warning against AI's abilities and how it must be regulated to prevent a disastrous outcome.

Now, the Tesla CEO has come together with a group of 116 specialists from across 26 countries to warn the United Nations about the dire ramifications of unregulated AI.

The group sent a letter to the international governing body just as it was slated to start formal discussions related to weapons including drones, tanks, and automated machine guns.

"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," the letter, released by the Future of Life Institute, reads.

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

The letter says action must be swift because when this "Pandora's box is opened, it will be hard to close."

But Musk isn't the only one warning against the potentially disastrous consequences of the technology.

Roger McNamee, founding partner of the venture capital firm Elevation Partners, told CNBC on Monday that "horrific things are likely," when you implement autonomous technology to weaponry.

"Think about this with automobiles. We never thought of automobiles as terrorist weapons. But once you start applying them that way, they're really terrifying," McNamee said. "And I think that's the issue. ... [I]t's going to be super hard to control how bad people use that technology once it's developed. Bad people are unlikely to observe the rules. There's a lot of history suggesting that fear is legitimate."

Musk, along with the other 116 specialists hope the UN adds "morally wrong" deadly automated weapons to the list banned by the body under the 1983 convention on certain conventional weapons (CCW).

"Unless people want to see new weapons of mass destruction - in the form of vast swarms of lethal microdrones - spreading around the world, it's imperative to step up and support the United Nations' efforts to create a treaty banning lethal autonomous weapons. This is vital for national and international security," the letter warned.

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