Iranian Supreme Leader reportedly orders military cooperation with US against Islamic State, in shift timed with final round of talks.

Reports on Friday indicated that Iranian Supreme Leader Ayatollah Khamenei authorized his army to coordinate joint military operations with the United States against the Islamic State (IS, formerly ISIS) in Iraq.

Iranian sources in Tehran told BBC Persian about the development, which comes as the Sunni extremist group that has conquered vast swathes of Iraq and Syria continues to threaten the Shi'ite Islamic regime of Iran.

According to the sources, Khamenei gave the orders to General Qassem Soleimani, commander of the elite Quds force that is a special operations unit of the Revolutionary Guards for international missions.

Soleimani was tasked with coordinating the moves with US, Iraqi and Kurdish forces, even though Iran has until now opposed US military involvement in Iraq. Recently he has been active helping Shi'ite militias strengthen Baghdad against the IS threat.

On Monday the northern Iraqi city of Amerli was captured by US and Iraqi forces, with pictures on the internet showing Soleimani in northern Iraq. BBC speculates this may mean the Iranian cooperation may have already begun.

While Khamenei has previously opposed US action in Iraq, US airstrikes have been proving effective in the country; recent airstrikes either by US or US-trained Iraqi forces on Thursday took out 18 IS leaders in Iraq, including an American jihadist leader.

Also on Thursday, airstrikes in Syria took out a top aide to IS leader Abu Bakr al-Baghdadi along with a senior IS military commander, Abu Alaa al-Iraqi.

A strategy amid failing nuclear talks?

As far back as in June when the IS threat was first becoming fully recognized, Prime Minister Binyamin Netanyahu warned America not to join forces with Iran against IS in Iraq, saying "both of these camps are enemies of the United States, and when your enemies are fighting each other, don't strengthen either one – weaken both."

While it has not yet been confirmed what America's reaction to the reported requests for cooperation will be, the news comes at a sensitive time as the US and world powers are continuing in likely the last round of flailing nuclear talks with Iran over its nuclear program, ahead of a November 24 deadline.

That deadline was previously extended after a July 20 deadline came and went, but Israeli officials have warned Iran is taking full advantage of the talks to advance its nuclear program, which it has blatantly threatened to use to destroy Israel in the past.

Ahead of leading an Israeli delegation to the US to argue for a firmer stance on Iran, Intelligence Minister Yuval Steinitz warned on Wednesday that "after a year of talks, Iran is closer than ever to achieving nuclear capabilities."

Steinitz added that as of today Iran has directly and indirectly invested over $200 billion into its nuclear program to this point, and that the Islamic regime has only made "small concessions" in the talks, not budging "even a millimeter" on core issues such as uranium enrichment.

It is worth noting that Khamenei back in January publicly revealed that the negotiations with the US about Iran's nuclear program are merely a tactic to stall international pressure and gain time to continue nuclear development.

Iran has also been active in attacking Israel, with senior Iranian officials revealing last month that the Islamic regime is arming terrorists in Judea and Samaria, and vowing it would continue supporting “the resistance” against Israel.