WASHINGTON, Feb 9: An US think-tank urged the Bush administration on Friday to pull out troops from Iraq because it believes that the United States can no longer win the war.

The Council on Foreign Relations report examines President Bush’s ‘surge’ plan as well as alternatives offered by his critics and concludes that a US military victory is impossible in Iraq.

Instead, the report favours a gradual “disengagement” of US forces to begin after six months of the surge -- the earliest point at which US military officials have said they can assess the surge’s impact. Under a gradual drawdown, troops would be withdrawn within 12 to 18 months, while efforts are intensified to carry out a regional stabilisation plan.

The report blames the administration’s "amateurish" post-invasion plan for plunging Iraq into a civil war. "The United States has already achieved all that it is likely to achieve in Iraq... Staying in Iraq can only drive up the price of those gains in blood, treasure and strategic position," writes Steven Simon, author of the report.