Experts react after the US military carried out air strikes against Iranian forces Iran-backed militias in Syria and Iraq in response to a drone attack that killed three American soldiers at a base in Jordan. The US retaliatory strikes amount to "a significant escalation" even though Washington and Tehran “have been very careful to make clear that they are not interested” in a direct conflict, says Allison McManus, the managing director for the national security and international policy department at the Center for American Progress. SOUNDBITES