The most senior U.S. military officer raised the possibility on Tuesday that American troops might need to take on a larger role in Iraq's ground war against Islamic State militants, but the White House stressed they would not deploy on a combat mission.
World powers backed military measures on Monday to help defeat Islamic State fighters in Iraq, boosting Washington's efforts to set up a coalition, but made no mention of the tougher diplomatic challenge next door in Syria.
The Syrian military's air defenses would face retaliation if Syria attempted to respond to U.S. air strikes that are expected against Islamic State targets in Syria, senior U.S. officials said on Monday.
President Barack Obama has chosen retired Marine Corps General John Allen, who served as the top U.S. commander in Afghanistan, to coordinate international efforts to fight Islamic State militants in Iraq and Syria, a U.S. official said on Friday.
