There was no evidence the helicopter had been attacked, he said. Eight soldiers, one police officer and one civilian were killed in the crash.
Other details were not immediately available.
More than 3,000 people have been killed in Thailand's southernmost provinces since the insurgency erupted in early 2004.
Muslims in the three southern provinces of Yala, Pattani and Narathiwat -- the majority in Buddhist Thailand's far south -- accuse the central government of discrimination, especially in jobs and education.
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