"We are obviously very concerned about what we're seeing in the city," said Major General William Caldwell, a spokesman for the U.S.-led coalition in Iraq.
"We're taking a lot of time to go back and look at the whole Baghdad security plan. We are asking ourselves if the conditions under which it was first devised and planned still exist today or have the conditions changed and, therefore, modifications to that plan need to be made," he added.
The U.S. military says attacks have increased by 20 percent in the past three weeks in the Iraqi capital.
Seventy-one U.S. soldiers have been killed in Iraq this month, one of the worst for U.S. forces since the March 2003 invasion.