EDIT-01: For clarification by AI, I mean AGI — not just ML, Generative AI, etc.
EDIT-02: To broaden question, I happy to expand it to any “stealth” projects known to have 10-million or more in funding explicitly for AGI, not just ML, Generative AI, etc. If for example OpenAI was a stealth project, which to my knowledge it’s not, or at least what’s commonly known of it, it would though count as a stealth project with 10-million plus in funding if they were not actively posting information or access to significant areas of progress, since their end goal is AGI.
https://www.theverge.com/2019/7/31/20746926/sentient-nationa...
It's unclear from public reports how capable the program is, but the NRO is known to have tech that is decades ahead of the civilian world - feel free to look this up, it's true. So honestly, I'd say that there's a decent chance some kind of AGI has ALREADY been invented.
Think it is safe to say that there are secret government projects on AI and those who know about them are staying silent to avoid treason charges. To find information about big projects on AI you can look at the various think tank websites, they generally have good information but tend towards the theoretical.
Theory of mind right now and the last 50 years are speculative and we have no real insight beyond connectionist views and some neuron models. Statistics can emulate aspects of vision and language but to call it "comprehension" is a stretch.
The Manhattan scientists worried they might miss the mark but that mark existed as a certainty. AI is where a metaphorical take on the nuclear age is: one of the scientists had a lump of "wood" and a match, and asked people to set it on fire: it was petrified wood. He used that as the metaphorical mountain they had to climb.
Ai doesn't even have the match yet.
A Manhattan project is a goal seeking investment by state actors to a highly specific endpoint. HIV vaccination, polio eradication, fusion energy.
What we have is DARPA engineering funding to outsider project breakthroughs. It's three orders of magnitude less certainty and funding is commensurate.