A new U.S. government report says that fuel for Afghanistan's security forces, paid for by the U.S., may include Iranian fuel in contravention of U.S. sanctions -- and implies that Turkmenistan may be to blame.
The report is by the Special Inspector General for Afghanistan Reconstruction , a U.S. government oversight agency that investigates possible abuse of U.S. funds in Afghanistan. While Afghanistan gets a majority of its fuel supplies from neighboring Iran, for fuel that the U.S. buys -- which includes that for the security forces -- suppliers have to abide by U.S. regulations prohibiting commerce with Iran. The companies that buy the fuel are Afghan-owned, but most of the fuel comes from Kazakhstan and Turkmenistan, with lesser amounts coming from Russia and Uzbekistan. But, as the report  notes, that fuel is often "blended" from different sources by the suppliers, and the oversight mechanisms that ensure that no Iranian oil is included are weak.
That there is no oversight is hardly surprising, but there is little positive evidence that the U.S. is actually buying Iranian oil. Still, the report does say that there is some suspicion, and it is directed at Turkmenistan:
According to SIGAR investigators, a fuel vendor in Afghanistan stated that Afghanistan’s neighboring countries to its west may be exporting blended fuel from various sources, including Iran....
In response to a draft of this report, the U.S. Embassy in Kabul stated that it is possible that if blending is taking place in Turkmenistan it could contain some Iranian fuel; however, it would be very unlikely that fuel imported from refiners in Russia and transitioned through Kazakhstan and Uzbekistan would be blended with Iranian fuel prior to its import into Afghanistan.
It's very hard for anyone, even diplomats based in Ashgabat, to know what is happening in Turkmenistan, so it's certainly possible for Turkmen companies to be pulling the wool over the Americans' eyes. Apparently undeterred, the Pentagon says that it spent over $800 million  in Turkmenistan over the last year, most likely on fuel. How much of that might be Iranian? We'll probably never know.