Sunni lawmakers pull out of talks to form a government over the killings . U.S. 'understands the threat ' U.S. President Barack Obama authorized targeted airstrikes to protect U.S. personnel in Iraq -- including military advisers -- as well as minorities being brutalized by ISIS . Reuters vows retribution for killing of three of its fighters in Syria . Steven Sotloff gunmen were militiamen , American lawmaker says . Sunni lawmakers pull out of government negotiations over killings .
Sunni lawmakers pull out of talks to form a government over the killings . Reuters vows retribution for killing of three of its fighters in Syria . Steven Sotloff gunmen were militiamen , American lawmaker says . Sunni lawmakers pull out of government negotiations over killings .