633
And , broad opposition to the U . S .- led attack on Iraq threatens to lead to a backlash by militant Islamists .
 U . S: attacker
Given event type and trigger, please tell me the arguments of all the listed option. Output format is "name1: role1; name2: role2". 
Event type: attack 
  Option: victim, attacker, place, target, instrument 
Text: {0} 
Answer:
 U . S: attacker