This article is from the Tehran Times, so take it with a grain of salt. But does any or all all of this sound plausible...?
Let me add... I agree on the Saudi non-response by the U.S, and it stands to reason about China's energy investments in Africa being a threat. However, elsewhere, I found a blogger's response to the article, so can't discount Roberts motives if we are to believe this response...
I wouldn't be surprised if this is what the whole matter is really about. We're a globalized world and there's no doubt that there's a power struggle between nations. And the US will try and prolong the inevitable: losing authority as the major influence in the world.