U.S., Iran seek common ground against militants, but doubts persist

Militant Islamist fighters parade on military vehicles along the streets of northern Raqqa province June 30, 2014. REUTERS/Stringer

WASHINGTON (Reuters) - Whether Washington likes it or not, Shi'ite Iran, a key ally of the governments of Iraq and Syria, is all but certain to be a major player in the fight against the Sunni militants of Islamic State.

Bitterly at odds over most major Middle Eastern issues, the United States and Iran now essentially find themselves on the same side in an escalating crisis over the Islamist group that has seized large swathes of Iraq and Syria.