Army spokesman Major General Athar Abbas said one soldiers was also killed and three others wounded during the firefight with the insurgents.
The military launched an operation in Swat, located 140 km from Islamabad, early this month after the militants failed to honour the terms of a peace deal.
According to the official claims, some 1,100 militants and more than 60 soldiers have so far been killed in the operation, which has also displaced more than 2.4 million people from Swat and its three neighbouring districts.
The military said it had made considerable progress in Mingora, the main town in Swat, and managed to arrest eight militants during house to house search.
"Mingora city will be cleared of militants in next 2-3 days," Abbas said.
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