Compounding the violence has been a massive prison break at the notorious Abu Ghraib prison, which led to the escape of at least 250 militants. Al Qaeda has claimed responsibility for their release, and Interpol has deemed the breach "a major threat to global security."

Earnest said that the U.S. had "long acknowledged" that it would require "a sustained effort to overcome" the challenges posed by the terror group. But, he said that the Iraqi government "has recaptured a number of prisoners who escaped and is in pursuit of others to return them to captivity."

"The Iraqis are responsible for their own security and their ability to provide for it is evolving," Earnest continued. "We are consulting closely with the Government of Iraq on ways to enhance their efforts and remain deeply committed to support the Government of Iraq’s efforts to bring greater stability and prosperity to its people."

Violence in the country has fueled concern that al Qaeda or other militant elements could be reinvigorated, intensifying concern that sectarian disputes could devolve into a civil war.