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In northern Iraq , U . S . warplanes struck a convoy of allied Kurdish fighters and U . S . special forces Sunday in one of the deadliest friendly fire attacks of the war .
 attack: struck
Please tell me event type and its trigger word from given type options. Output format is "type: trigger".  Option: declare bankruptcy, transfer ownership, marry, die, phone write, arrest jail, convict, sue, transfer money, end organization, start organization, end position, merge organization, start position, transport, charge indict, elect, attack, injure, born, extradite, release parole, sentence, demonstrate, meet, trial hearing, divorce, nominate, fine, appeal, pardon, execute, acquit 
Text: {0} 
Answer:
 attack: struck