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After the departure of Soviet troops in 1989 , the People 's Democratic Party of Afghanistan regime , then headed by Mohammad Najibullah , held its own against the mujahideen .
 organization: Soviet troops; organization: People 's Democratic Party of Afghanistan; person: Mohammad Najibullah
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 organization: Soviet troops; organization: People 's Democratic Party of Afghanistan; person: Mohammad Najibullah