The explosion hit a truck in Chin Swe Haw town, in northern Shan State's Laukkai district, in the early hours of yesterday morning, the Burmese language Myanma Alinn newspaper said.
Two men and a woman were killed by the blast, while another three were being treated in hospital.
The paper reported that officials found another improvised explosive device near the scene of the first blast that had not detonated.
The fighting forced tens of thousands of refugees to flee into neighboring China earlier this year, causing a spike in tensions between Beijing and Naypyidaw.
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