BBC Persian claims that, in a remarkable shift of position, the Supreme Leader has approved co-operation with the US in the fight against the Islamic State in Iraq.

Ayatollah Khamenei, through high-level officials, had firmly vetoed the Rouhani Government’s consideration of cooperation, following the Islamic State’s capture of Mosul and Tikrit and advance towards Baghdad in June.

The Supreme Leader’s objection to cooperation with the US was expressed through speeches, where he denounced the dishonesty of Washington, and through claims from the military and politicians — including Speaker of Parliament Ali Larijani — that the US had helped create the jihadist threat of the Islamic State. Earlier this week, those allegations were repeated.

However, the BBC cites “sources in Tehran” that the Supreme Leader has authorised the Revolutionary Guards to coordinate military operations with the US, as well as Iraqi and Kurdish forces.

David Ignatius of The Washington Post offers support for the claim. Presumably briefed by unnamed US officials, he writes today, “the United States has opened a quiet back channel to Iran to ‘deconflict’ potential clashes as both countries use air power to attack Islamic State targets. That’s sensible policy, and maybe the start of broader liaison discussions.”

(Significantly, Ignatius refers to Iranian air rather than ground operations. Tehran has not acknowledged that it has carried out any sorties, although there have been unconfirmed claims of Iranian aircraft flying over Iraq.)

The Iranian Foreign Office

#Iran FM Sopxwoman denies BBC's report that Iran's SL Khamenei approved cooperation with the #US as part of the fight against #ISIL in #Iraq

— Mehdi Sayyari (@mehdisayyari) September 5, 2014

” target=”_blank”>denied the claims this afternoon.

Earlier, the story was rebutted through a message to Thomas Erdbrink, the Tehran correspondent of The New York Times:

On Sunday, the US and Iran both assisted the Iraqi and Kurdish troops in the breaking of the two-month siege of Amerli in northern Iraq. The Americans bombed Islamic State positions, while Iranian advisors on the ground assisted the Iraqi-Kurdish counter-offensive.

After the victory, photographs circulated of General Qassem Soleimani, the head of the elite Qods Force of the Revolutionary Guards, in Amerli.