This includes assessing troop levels and focusing on how best to train Iraqi soldiers and police.
In a move some lawmakers and military analysts said showed the concern of senior Pentagon officials for the Iraqi situation, retired Army General Gary Luck will have "extraordinary leeway" to look at the Iraqi operation, identify weaknesses and report back in a few weeks with a confidential assessment, Pentagon officials said on Friday.
"He will have a very wide canvas to draw on," said Pentagon spokesman Lawrence Di Rita, adding that Rumsfeld was very satisfied with his commanders in Iraq, but wanted to give them all the help they needed in assessing what he described as a very dynamic situation.
Rumsfeld announced his decision on Luck's mission at a meeting on Thursday with his top military and civilian aides, senior defence officials said.
Luck, a former head of US forces in South Korea who served as senior adviser to top US General Tommy Franks during the Iraq war of 2003 and is currently a senior adviser to the military's Joint Forces Command, will head a small team of military specialists while conducting his review in Iraq, the sources said.
Luck's mission will be a more open-ended version of other spot assessments the military has conducted in Iraq and Afghanistan, from the training programme in Iraq to the enhancement of intelligence collection.