Incident took place in Kech district in southwestern Baluchistan province, which shares a long lawless border with Afghanistan and Iran.
Pakistan’s army said attackers from Iran killed four of its border patrol soldiers.
“A group of terrorists operating from Iranian side attacked a routine border patrol of Pakistani security forces operating along Pakistan-Iran Border,” the military’s media wing ISPR said in a statement on Saturday.
“Necessary contact with Iranian side is being made for effective action against terrorists on the Iranian side and to prevent such incidents in future.”
The incident took place in Kech district in southwestern Baluchistan province, which shares a long lawless border with Afghanistan and Iran. No one has claimed responsibility.
Pakistan and Iran share more than 900km (45 miles) of border. There have been several security incidents in the past.
Rebel Baluch nationalist groups in the area say they are fighting for a greater share of regional resources. The Baluch groups operate on both side of the border.
In January, at least 13 people were wounded after an explosion in a passenger train in the province’s Bolan district.