With momentum building for international military action against Islamist extremists in Syria, the United States reiterated Friday it will **t coordinate with strongman Bashar al-Assad in the effort. "The answer to the security challenges is **t the Assad regime," State Department deputy spokeswoman Marie Harf told reporters. "They have lost legitimacy to lead, period." An Assad advisor, Buthaina Shaaban, was quoted by state news agency SANA earlier Friday saying Damascus must be included as a "key part" of the multinational coalition that US President Barack Obama an**unced Wednesday in his strategy to defeat jihadists k**wn as the Islamic State (IS). We will **t be coordinating with the Assad regime." US lawmakers have spoken of the extraordinarily complex situation on the ground in Syria, where various rebel groups are fighting Assad forces.