Iran's Revolutionary Guards said Friday they had killed four militants who had slipped across the border from Pakistan to try to carry out an attack.
The Guards said two militants were also wounded in the clash in the southeastern province of Sistan-Baluchistan, with the "rest of the terrorists fleeing to the soil of the neighbouring country".
Sistan-Baluchistan has a large, mainly Sunni Muslim ethnic Baluchi community, which straddles the border into the Baluchistan province of neighbouring Pakistan.
Sunni extremist group Jundallah (Soldiers of God) launched a bloody insurgency in the province in 2000 targeting the security forces and officials of Iran's Shiite-dominated government.
The campaign peaked with a spate of deadly attacks from 2007 -- including twin suicide bombings against a Shiite mosque that killed 28 people -- but abated after the group's leader was killed in mid-2010.
In 2012, Jundullah members formed a successor organisation called Jaish al-Adl (Army of Justice), which has carried out a spate of attacks on the security forces.
Iran has alleged that the group has received support from the US, British and Israeli intelligence services with the complicity of Pakistan.
In a statement on their Sepah News website, the Guards said the overnight clash on the Pakistani border came after "intelligence operations by the Guards' ground forces revealed that a terrorist team linked to global arrogance planned to attack the Islamic republic's border posts on (Friday) morning."