As others have mentioned, this specific concern may not be much of a problem. It might be that it's easier to deliver a nuclear bomb the old-fashioned way than putting it in a fake person.

However, I agree that development of AI should be done with caution. The work of the Singularity Institute is worth looking into; see http://commonsenseatheism.com/wp-content/uploads/2012/02/Mue... for a more academic summary and http://facingthesingularity.com/ for a longer popular summary of their positions.