Washington has been unable to reach an agreement with Bahgdad on the US demand for granting immunity to US soldiers on Iraqi soil, which means an end to the presence of US military in Iraq after the end of 2011 , the date set for the withdrawal of US forces. A US official said the US has now 40,000 troops in Iraq who will all leave by the end of this year. The official said the US would maintain substantial presence near Iraq in case pending issues between the two sides are settled.