The Pakistani army says "terrorists" operating from Iran have killed four of its border patrol troops in the south-western province of Balochistan.
An army statement said officials were talking to their Iranian counterparts to prevent such incidents in future. The attack happened in Kech district.
No group has yet claimed responsibility for the attack.
Separatists in Balochistan have been fighting the government for decades. The province has a long, porous border.
Reports said the insurgents had taken the weapons of the four dead soldiers. The army statement included photos of the four: a corporal, a lance-corporal and two privates.
Last month nine Pakistani security officers were killed and at least 13 wounded in a suicide attack in Balochistan.