The U.S. government and Saudi Arabia have worked together to turn China against Iran to achieve tighter sanctions against Tehran since 2009, according to Wikileaks.

And now the U.S. government is working to keep China from investing further in the Iranian oil business, according to Reuters.

The leaks detail how Saudi Arabia offered to replace crude output China receives from Iran in exchange for support at the UN for tighter sanctions against the country. This deal-making goes back as far as 2009.

These sort of diplomatic tactics were hinted at in earlier Wikileaks, but the latest reports are far more graphic.

Via Reuters, in 2009:

Two months earlier, a senior French diplomat overseeing Middle Eastern affairs told a U.S. embassy official that Saudi diplomats had told China: "If you want oil from us ... then you must put more pressure on Iran."

China has also acted as a go-between in negotiations between the U.S. and Iran over nuclear issues, according to the reports.

While Chinese companies are now getting more involved with the Iranian oil industry, the U.S. is doing its best to deter China here too.

The U.S. government is now offering China access to its energy market in exchange for cooperation over Iran, according to Reuters.

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