The Iranian Air Force is bombing Islamic State (ISIS) targets inside Iraqi territory. It is an intensification of Iran's military involvement on the side of the Shia regime of its neighbor and most likely also a sign of its alleged coordination with the U.S. military which is leading the international coalition fighting ISIS.

The first footage of an Iranian aircraft bombing inside Iraq was broadcast by Al Jazeera a few days ago in a report on a joint operation by the Kurdish Peshmerga forces, Iraq's army and Shia militias to recapture two Kurdish towns in northeastern Iraq, near the Iranian border. The report mentions "Iraqi jet-fighters," but the plane seen bombing ISIS positions is a F-4 Phantom, which is not in Iraqi service.

The venerable Phantom which first entered service in 1960 (and was retired by the U.S. Air Force in the 1990s and Israel in 2004) still flies with two air-forces in the region, Turkey and Iran. The Phantom's markings are not visible in the Al Jazeera footage but since Turkey has so far refused to militarily aid the Kurds fighting across the border and the proximity to Iran, it is almost certainly an Iranian fighter.

In recent months Iran has increased its military assistance to the Iraqi army which is on the brink of collapsing in the face of ISIS advance and has also established and equipped Shia militias. In addition to the military advice and arms supplies, there have been multiple reports of active participation of members of Iran's Revolutionary Guards (IRGC) in the fighting and unconfirmed reports of the deployment of Iranian aircraft to airfields in Iraq, but the Al Jazeera footage is the first documented of Iranian air attacks on Iraqi territory.

The Obama administration has repeatedly denied that it is coordinating with Iran military action against ISIS, though U.S. officials have admitted that the issue of ISIS has come up during meetings with Iranian representatives regarding the talks on Iran's nuclear program. Last month, following the report in the Wall Street Journal on a personal letter sent by President Barack Obama to Iran's Supreme Leader Ali Khamenei, U.S. national security adviser Susan Rice said that "we are in no way engaged in any coordination - military coordination - with Iran on countering ISIL."

However it is highly unlikely that fighter-jets would be operating in the same area where dozens of American planes, along with those of other air-forces of the international coalition, are also carrying out attacks against ISIS, without significant coordination. Iran has only a limited number of antiquated combat aircraft, such as the F-4, purchased during the rule of the Shah, before the 1979 Islamic revolution, and still flying for nearly four decades thanks to a great deal of creative maintenance. They wouldn't be risking these in American-dominated airspace if they hadn't received assurances that they were liable to be shot down. The Phantom captured by an Al Jazeera camera crew is proof that coordination between the two sides is going at some level.

