"Two soldiers were martyred and one injured when militants from Afghanistan opened fire on Pakistani troops," a senior security official said.
He said the incident took place in the Barmal area of South Waziristan, which shares its borders with Afghanistan's Paktika province.
Three FC soldiers gunned down in Quetta
The incident was confirmed by local administration officials and other senior security sources.
No one immediately claimed responsibility for the attack.
The army launched the operation in mid-2014 to wipe out militant bases in the area and end the near decade-long insurgency that has cost Pakistan thousands of lives.
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