Iran's Islamic Revolution Guard Corps (IRGC) has claimed breaking up a militant cell responsible for a suicide bomb attack last week that killed 27 servicemen.
"Last night, a terrorist cell was identified and destroyed in an operation," the Corps said in a statement carried by the semi-official Tasnim news agency.
Three militants were arrested and 150 kilograms of explosives was seized from houses in the cities of Saravan and Khash, it said.
"They were linked to the suicide bombing attack last week. The Corps will continue its efforts to take revenge over the deadly terrorist attack," it said.
The IRGC is under pressure to show it is in control of the country's security as more terror attacks have been taking place. But Iran rarely shows evidence of militants it claims it arrested or weapons and explosives captured.
The Sunni group Jaish al Adl (Army of Justice), which says it seeks greater rights and better living conditions for the ethnic minority Baluchis, claimed responsibility for the latest attack.
Iran says militant groups operate from safe havens in Pakistan and have repeatedly called on the neighboring country to crack down on them.
Iranian authorities also accuse regional rival Sunni Saudi Arabia and the United Arab Emirates of financially supporting militant Sunni groups that attack Iranian forces. Pakistan, Saudi Arabia and the UAE deny backing such militants.
Iran summoned the Pakistani ambassador to protest the attack.
Iran says it provided Pakistani officials with "information on the terrorist groups' hidden and semi-hidden training centers", army chief-of-staff Mohammad Bagheri told Tasnim news agency.
In a phone call with Pakistani army commanders, Bagheri asked them to "either confront the groups or allow (Iranian) forces to enter."