Iran's Revolutionary Guard Corps said on Friday it had killed four militants at the Saravan border crossing with Pakistan in Iran's southeastern Sistan-Baluchestan province.
Sunni militant groups in southeastern Iran have long carried out periodic attacks on military and civilian targets, aiming to highlight what they say is discrimination against Sunni Muslim ethnic groups in mainly Shia Iran.
In a statement published by state broadcaster IRIB, the Revolutionary Guard said "Iranian forces killed four terrorists and wounded two. Other members of the terrorist group fled to the neighbouring country (Pakistan)".
No Iranian forces was harmed in the attack, the statement said.
The Guards said the group was linked to the "world's arrogant power", without elaborating. Tehran accuses the United States, Israel and Saudi Arabia of funding Sunni militant groups, a charge they deny.
The mainly Sunni province of Sistan-Baluchestan has long been plagued by unrest from both drug smuggling gangs and separatist militants.
Iran says militant groups have safe havens in Pakistan and has warned it will hit their bases there if Islamabad does not confront them.
Security measures have intensified in border areas after an attack on Saturday at a military parade in southwestern Iran in which five gunmen killed 25 people, almost half of them Revolutionary Guards.