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Well , at least three U . S . service members were killed today in an apparent suicide bomb attack at a checkpoint near the Haditah Dam northwest of Baghdad .
 geographical social political: U . S; geographical social political: Baghdad; organization: U . S . service; person: at least three U . S . service members; facility: a checkpoint near the Haditah Dam northwest of Baghdad; facility: the Haditah Dam northwest of Baghdad; weapon: bomb
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: organization, person, geographical social political, vehicle, location, weapon, facility 
Text: {0} 
Answer:
 geographical social political: U . S; geographical social political: Baghdad; organization: U . S . service; person: at least three U . S . service members; facility: a checkpoint near the Haditah Dam northwest of Baghdad; facility: the Haditah Dam northwest of Baghdad; weapon: bomb