As technology advances, such prohibitions are going to become less and less effective.

Tech is constantly getting smaller, cheaper and easier for a random person or group of people to acquire, no matter what the laws say.

Add in the nearly infinite profit and power motive to get hold of strong AI and it'll almost impossible to stop, as governments, billionaires, and megacorps all over the world will see it as a massive competitive disadvantage not to have one.

Make laws against it in one place, your competitor in another part of the world without such laws or their effective enforcement will dominate you before long.