"I do believe it's possible that we could adjust our forces, downsizing them in the course of next year. That's possible given the positive political developments and the continuing growth in the capabilities of the Iraqi forces," Ambassador Zalmay Khalilzad said at the White House on Wednesday.
The diplomat pointed to the approval of Iraq's constitution in a national referendum that he said had been marred by less violence than January elections thanks to improving Iraqi security forces.
"And as the political situation changes, as the Iraqi capabilities grow, we'll adjust the size, the composition and the mission of our forces, because the military commanders are very focused on this. They make recommendations to the president," he said.
"The composition of the forces that we have there and their mission are not ends in themselves for us. What it is, is Iraq being able to stand on its own feet. That's the end: Iraq succeeding," Khalilzad told reporters.
Ambassador Zalmay Khalilzad says
the US is winning the war in Iraq
Calls for US President George Bush to set a firm timetable for withdrawing the roughly 150,000 US troops in Iraq have multiplied, as public opinion polls have found the war in Iraq increasingly unpopular.
Senator John Kerry, whom Bush defeated in last year's presidential election, has meanwhile said the president should bring home 20,000 troops from Iraq over the Christmas holidays if the December parliamentary elections are successful.
Kerry on Wednesday called for a "reasonable time frame" for pulling back troops rather than a full-scale withdrawal advocated by some Democrats. He said it could be completed in 12 to 15 months.
Kerry is critical of the Bush
administration's strategy in Iraq
"It will be hard for this administration, but it is essential to acknowledge that the insurgency will not be defeated unless our troop levels are drawn down ... starting immediately after successful elections in December," Kerry said in a speech at Georgetown University in Washington, DC.
The presence of US troops in Iraq is deterring peace efforts, said Kerry, a member of the Senate Foreign Relations Committee.
"To undermine the insurgency, we must instead simultaneously pursue both a political settlement and the withdrawal of American combat forces linked to specific, responsible benchmarks," he said.
"At the first benchmark, the completion of December elections, we can start the process of reducing our forces by 20,000 troops over the course of the holidays."