2316
for a week now , protesters have been clashing with police and backers of the clerical regime in tehran .
 tehran: place; protesters: target; police: target; backers: target; protesters: attacker; police: attacker; backers: 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:
 tehran: place; protesters: target; police: target; backers: target; protesters: attacker; police: attacker; backers: attacker