In recent days, Iran has conducted airstrikes against the self-proclaimed "Islamic State" (IS) terror group in Iraq, a US official said on Tuesday.

Comments from the Pentagon came after reports that American-made F4 Phantom jets from the Iranian air force had been targeting IS in the eastern Iraqi province of Diyala.

"We have the indications they have flown these missions in recent days in eastern Iraq," Pentagon spokesman Rear Admiral John Kirby said.

Uncoordinated attacks

Iranian forces had already been active on the ground in assisting Shiite militia and Baghdad government units, but this was the first time that the US had confirmed that Tehran had launched manned aircraft from inside Iran to strike Islamic State targets in Iraq.

The strikes, however, were not coordinated with the US. "Nothing has changed about our policy of not coordinating military activity with the Iranians," Kirby said.

Iran has previously offered help to the coalition in the fight against IS, but its request was refused by the US, which has vowed it would not coordinate with Iran on military actions inside Iraq.

Washington is concerned that Iran, which backs the majority Shiite government, will provoke further resentment among Iraq's Sunni minority.

"We ask that they do those things in keeping with the idea that we don't further inflame sectarian tensions inside Iraq," Kirby added.

ksb/jm (AFP, dpa)