Iranian troops have helped Iraqi government forces re-take the town of Tikrit, the Wall St Journal reports Iranian security sources as saying.
The source said that two battalions of Iran's Quds force, the overseas branch of the country's Revolutionary Guard, helped battle ISIS Islamist militants in the city.
A combined Iraqi-Iranian force has now taken control of 85% of the city, the sources added.
The Foreign Secretary has been clear on the threat of Isis, but he has ruled out the prospect of any UK military involvement in the crisis.
Iraq’s foreign minister, Hoshyar Zebari, is a natural diplomat. Polite, immaculately dressed, and blessed with a great memory.
Isis has paraded military equipment in Mosul it captured from when the Iraqi army fled in what some see as a "nightmare scenario."