Adel Abdel-Mahdi, Iraq’s vice president, has expressed concern over a weakening of American political engagement in Iraq, and predicted that some troops could remain beyond the 2011 withdrawal deadline to train and assist Iraqi forces, but not to engage in combat operations.

Mr Abdel-Mahdi, however, insisted that Iraqis themselves now had to take up the challenge of governing, and that the recent surge in violence should not derail US plans to withdraw its troops.