Baghdad, Aug 13 (IANS): An umbrella group of Iraqi Shia militias warned the US of "unlimited" retaliation if it attacks Iraq or Iran.

The Iraqi Resistance Coordination Committee (IRCC), representing the Islamic Resistance in Iraq, said on Monday that it would not be constrained by any restrictions if US forces target Iraqi personnel or use Iraqi airspace to strike Iran.

This threat comes amid heightened regional tensions, with Iran and its allies pledging retaliation for the recent killings of Hamas Politburo Chief Ismail Haniyeh in Tehran and Hezbollah commander Fouad Shokor in Beirut, both occurring in late July, Xinhua news agency reported.

In response to the rising threat, Washington said it is committed to defending Israel in the event of a major conflict and is sending "more troops and military hardware to the Middle East".

The Iraqi resistance has been actively opposing the US military presence in Iraq and has previously claimed responsibility for attacks on US targets, including a recent rocket strike on the Ayn al-Asad Airbase in Anbar province, which houses US troops.