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The nuclear standoff began in October , when U . S . officials said North Korea admitted having a secret nuclear program in violation of a 1994 agreement .
 geographical social political: U . S; geographical social political: North Korea; person: U . S . officials; weapon: nuclear; weapon: nuclear
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: North Korea; person: U . S . officials; weapon: nuclear; weapon: nuclear