A top US military officer in Baghdad has stirred controversy by arguing in a confidential memo that the American presence in Iraq has outlived its welcome and that it was time "for the US to declare victory and go home".

The memo, leaked to the New York Times, was written by Colonel Timothy Reese who calls for all US troops to be pulled out of Iraq by August next year. He draws on the adage "Guests, like fish, begin to smell after three days," adding: "Since the signing of the 2009 security agreement, we are guests in Iraq and after six years in Iraq, we now smell bad to the Iraqi nose."

Under that Status Force Agreement, the US has agreed with the Iraqi government to complete withdrawal by the end of 2011. Though the numbers of troops pulled out so far is limited, the US military has begun to quit Baghdad and other Iraqi cities.

The disclosure of the Reese memo comes a day after the US defence secretary Robert Gates said that the pull-back from Iraq could be sped up slightly with the inclusion of an extra brigade of about 5,000 troops by the end of this year on top of the two already planned. But that still leaves most US troops still inside Iraq at the time of the sensitive Iraqi elections in January.

Reese, an author of the official US army history of the Iraq war and a current adviser to the Iraqi military in Baghdad, is double-headed in his memo. He warns that there are still big problems within the Iraqi security forces, from corruption to ongoing political pressure from Shia politicians.

He also reports that since the US withdrawal of combat troops from Baghdad, there has been a "sudden coolness" shown by Iraqi military leaders towards US advisers. Iraqi units were now less willing to work with the Americans in joint operations.

Nonetheless, he goes on to argue that staying on will only foment further resentment among Iraqis.

The idea of a rapid acceleration in the pullout from Iraq was greeted with scepticism by Stephen Biddle of the Council on Foreign Relations in Washington, a former adviser to General David Petraeus. Biddle said that it was not in the interests of either the Iraqis or the US to speed up withdrawal.

Biddle said that the main problem facing the military in Iraq was an "identity civil war" between Shias and Sunnis and potentially between Arabs and Kurds, comparable to the Balkans.

"Our mission is peacekeeping stabilisation in Iraq. I would like to see a long, slow drawdown to the level of a peacekeeping force, as we saw in the Balkans," Biddle said.

He added that his impression was that neither General Ray Odierno, the top US commander in Iraq, nor Petraeus who now heads US central command, would agree with the call for a faster departure.

A spokesman for Odierno told the New York Times that the Reese memo was not intended for widespread dissemination and did not reflect the view of the US military.