Ask HN: How a real AI might be used as a weapon

When comparing a real (singularity) AI with the invention of other technologies (i.e. nuclear power) - its use as a weapon is probably inevitable. How do you imagine an AI beeing used within a international conflict. I just read some pro/con pieces about a singularity AI and the discussion feels a lot like utopia vs. end of the world ... ;-) Your thoughts?