(Tikrit, Iraq) -- Iraqi insurgents are promising more fighting after already taking control of two cities. A recording believed to be from the al-Qaeda linked Islamic State of Iraq and Syria urges the militants to take the fight to more Iraqi cities, including Baghdad. U.S. State Department Spokesperson Jen Psaki says the U.S. is concerned about the situation in Iraq.
Rebels now control the northern cities of Tikrit and Mosul, and are closing in on the country's biggest oil refinery. About a half-million Iraqis fled Mosul following the fall of the country's second biggest city.