The fighting between the insurgents and village members of the Basij militia took place in Kurdistan province, in a part of Iran where security forces and rebels have clashed in the past.
"These people were killed in a clash with Basijis ... on Tuesday night," IRNA said, without giving further details. The volunteer militia is estimated to have 12 million members across the Islamic Republic.
Iranian forces often clash with guerrillas from the Party of Free Life of Kurdistan (PJAK), an offshoot of the Kurdistan Workers Party (PKK) which took up arms in 1984 to fight for a Kurdish homeland in southeast Turkey.
Like neighbouring Iraq and Turkey, Iran has a large Kurdish minority, mainly living in the country's northwest and west.
Iran sees PJAK, which seeks autonomy for Kurdish areas in Iran and shelters in Iraq's northeastern border provinces, as a "terrorist" group.