Mortar shells were fired into Pakistan's territory from across the Iranian border, reports Samaa TV.
Pakistan shares a 900 kilometre long porous border with Iran and the two countries had in 2014 decided to boost intelligence coordination to wipe out terrorists from the border region.
Work on the Rs 20 million Pakistan Gate in Taftan along the Pak-Iran border was completed in 2016.
This border crossing point is the oldest trade route to Iran and Europe and thousands of foreigners and locals travelling to Europe and Iran by road each year use this crossing point.
Recently, the ties between the two neighbours got stressed after ten Iranian border guards were killed at Mirjaveh on the Sistan-Baluchistan border by the Pakistan-based Sunni terror outfit, Jaish al-Adl or "The Army of Justice".
Iranian police said the guards were killed by long-range guns and called on Islamabad to assume ultimate responsibility for the crime.The Sistan-Baluchistan province in south-east Iran has long been plagued by drug smuggling gangs and separatist militants.