US President Barack Obama has warned Iran to respect Iraqi sovereignty in the fight against Islamic State militants.
Shi'ite militias backed by Tehran have been playing a growing role against IS forces.
But President Obama says Iranian-backed groups must come under the command of Iraqi Prime Minister Haidar al-Abadi, with whom he has been holding talks in Washington.
Washington has announced an extra $200 million in humanitarian aid to Iraq.
And Iraq's Prime Minister insists his forces have retaken a quarter of territory seized by Islamic State militants.
But Tim Ripley from Jane's Defence Weekly cautions against over-optimism.
IN: "He really...
OUT: ...in Iraq."
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