"All members of the two groups were killed and many arms have been seized," said Iraj Hassanzadeh, a security official in the governor's office of Kordestan province.

"These groups were linked with terrorist and counter-revolutionary movements," he said, without giving any further details or the numbers killed.

Iran's northwestern Kurdish-populated areas have been the scene of deadly clashes with Kurdish separatist rebels of the Party of Free Life of Kurdistan (PJAK), which has bases in northeastern neighbouring Iraq.

Iranian military on Thursday also shelled three Iraqi border villages. The shells were apparently aimed at PJAK bases in the area, an Iraqi official said.

Tehran has repeatedly accused the United States of seeking to stir up ethnic unrest by providing material support to PJAK, which is linked to the Kurdistan Workers' Party (PKK).