US vows to help Iraq retake lost territories

US Vice President Joseph Biden has pledged "full support" for Iraqi efforts to retake territories lost to the Islamic State, as Baghdad bristled at the Pentagon chief's criticism of Iraqi forces over the battle against the extremist group.

In a phone call with Iraqi Prime Minister Haider al-Abadi on Monday , Biden reiterated "full US support" for Iraqi liberation efforts, including "the expedited provision of US training and equipment" to help combat the Islamic State's use of truck bombs in fighting, Xinhua reported cited White House statment.

Washington is rushing 1,000 antitank rockets to Baghdad after the Islamic State took full control of Ramadi, the capital of Iraq 's largest Anbar province in the west, on May 17 by using suicide vehicle bombs and other means.

US Defence Secretary Ash Carter on Sunday blamed Ramadi's fall on a lack of will on the part of the Iraqi forces to fight the Islamic State, which has announced the establishment of a caliphate in areas under its control in Syria and Iraq.

Al-Abadi told BBC on Monday that he was "surprised" at Carter's comment, vowing to launch a counter-offensive soon to take Ramadi back.

"The vice president recognised the enormous sacrifice and bravery of Iraqi forces over the past 18 months in Ramadi and elsewhere," the White House said in a statement.

Washington' current strategy on fighting the Islamic State needs ground operations by the Iraqi and Kurdish forces in support of the US-led air strikes on the group's targets.