US open to working with Iran against extremists

The Pentagon, however, quickly tamped down speculation that the United States would co-ordinate or consult with Iran on any potential military intervention. It also flatly ruled out the idea of “joint military operations” with Iranian armed forces, which the US has long accused of fomenting unrest and backing terrorism in Iraq and throughout the Middle East.
Kerry said Washington is “open to discussions” with Tehran if the Iranians can help end the violence and take steps that would restore confidence in the Iraqi government. Asked about possible military co-operation with Iran, Kerry said he would “not rule out anything that would be constructive”, but he stressed any contacts with Iran would move “step-by-step.”