In a letter released by the Pentagon, the chairman of the Joint Chiefs of Staff wrote that he was "disappointed at how quickly the situation in Iraq deteriorated as well as the rapid collapse of many Iraqi units."
Sunni militants, led by the Islamic State of Iraq and Syria, recently launched a lightning offensive to seize key Iraqi cities. In some areas, Iraqi troops abandoned their posts.
What is happening in Iraq, Dempsey wrote, is "part of a broader, regional struggle that extends from Baghdad to Beirut to Damascus. They reflect the political instabilities in the region and poor political choices by Iraq's leaders -- choices that fueled already complex and deep-seated sectarian tensions."
Dempsey acknowledged the accomplishments and sacrifices made by America's armed forces in the Iraq war. "The path forward will not be easy," he wrote.
"And, as always, we in the military are preparing options for the President to consider in addressing the emerging threats there."
Notable deaths of 2014 [PHOTOS]