Iran has reportedly deployed an elite unit of its Revolutionary Guard to support the Iraq Government in its fight against the Islamic State in Iraq and the Levant (ISIS), the Sunni militant group that is trying to further destabilise the war-torn country.
ISIS spokesperson Abu Mohamad al-Adnani said the fighters would march towards Karbala and Najaf to 'settle their differences' with Iraq Prime Minister Nouri al-Maliki.
Iranian security officials have been quoted by the Wall Street Journal as saying that two units were sent from Iran's western border provinces on 11 June.
They have been made responsible for protecting Baghdad, Karbala and Najaf, according to Iranian security officials.
An Iranian army general said that troops have also been deployed along Iran's border with Iraq, and the Iran Air Force has been instructed to bomb the rebel forces if they are found within 60 miles of the country's border.
Additional plans that could be implemented by Iran include the transfer of Shiite volunteer troops from Syria to Iraq.
When asked about the development, Iraqi Foreign Minister Hoshyar Zebari said: "Frankly I have no idea about that. I am in London now."
Meanwhile, Iran Foreign Ministry spokesperson Marzieh Afgham said: "Until now we haven't received any requests for help from Iraq. Iraq's army is certainly capable in handling this."
US State Department officials have declined to outline the action plan that would be taken by the Obama administration if Iranian forces support Iraq.