Fars news agency said the armed group had planned to carry out "terrorist activities" in the Islamic state. It did not make clear when the clash happened and did not give details about the identity of those killed.
Iranian media said last month nine militants and three Iranian Revolutionary Guards were killed in fighting in northwestern Iran near the Turkish border.
Iranian forces have often clashed in Iraqi border areas with militants from the outlawed Party of Free Life of Kurdistan (PJAK), an offshoot of the Kurdistan Workers Party (PKK).
"Some of the terrorists were killed in a clash with security forces and the others escaped to the other side of the border," Fars quoted Shahnam Rezai, a police official in the province of West Azarbaijan, as saying.
"Four border guards from the town of Piranshar were martyred in the clash and one was wounded," Rezai added.
Iran shares its western borders with Turkey and Iraq and a Turkish general said on Thursday his country was cooperating with Iran through the sharing of information and coordinated strikes against PKK guerrillas in northern Iraq.
General Ilker Basbug, the second most powerful man in the Turkish military, said the two countries had not carried out any coordinated strikes in the last "one or two months" but would do so if necessary.
The Turkish military has regularly attacked PKK rebel positions this year in the mountains of northern Iraq, where several thousands are believed to be holed up.
Analysts say PJAK has bases in northern Iraq from where they operate against Iran.
Güncelleme Tarihi: 06 Haziran 2008, 08:32