An Iranian military official says Tehran has proof that militants are entering Iran from Pakistan to carry out attacks.
Abdollah Araghi, a senior commander of Iran's Islamic Revolutionary Guards Corps, said on state television on October 18 that the issue will be pursued through "diplomatic channels."
He added that his forces have given documents to Iranian officials that show militants crossing into Iran from Pakistan.
Araghi's claim comes one day after Pakistan's Frontier Corps said Iranian border guards opened fire at a patrol van, killing a member of the Frontier Corps and wounding three others.
On October 16, Iranian Brigadier General Hussein Salami warned Pakistan that Iranian forces could enter Pakistani territory to "prevent terrorists" from coming into Iran.
Four Iranian guards were killed by unknown attackers in the eastern Iranian Province of Sistan-Baluchistan, which borders Pakistan.