Iran said on Tuesday it had arrested members of an extremist group in the west of the country who had planned to carry out "terrorist attacks" in the Islamic state, the official IRNA news agency reported.
Interior Minister Mostafa Mohammad-Najjar said the group, identified and arrested by the Intelligence Ministry, was armed and guided by American forces, IRNA reported.
Mohammad-Najjar did not identify the group or say whether those detained belonged to Kurdish separatist groups, based in mountainous areas close to the borders with Iraq and Turkey.
Iranian security 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 for an ethnic homeland in southeast Turkey.
Like Iraq and Turkey, Iran has a large Kurdish minority, mainly living in the country's northwest and west.
Tehran sees PJAK, which seeks autonomy for Kurdish areas in Iran and shelters in Iraq's northeastern border provinces, as a terrorist group.
Sectarian violence is relatively rare in Iran, whose leaders reject allegations by Western rights groups that it discriminates against ethnic and religious minorities.
Iranian officials often accuse the United States and Israel of supporting "terrorists." The United States dismisses such allegations.
The Islamic Republic is locked in a dispute with the United States and its allies over its nuclear program which Washington fears will allow Tehran to develop nuclear weapons. Iran denies any such intention.