Four troops from Iran's powerful Revolutionary Guards have been killed in clashes with Kurdish rebels in western Iran, the semi-official Mehr news agency reported Wednesday. Eight others were wounded.
The fighting erupted outside Paveh, a town near the Iraqi border.
There has been sporadic fighting in the mountainous regions on Iran's border with Iraq and Turkey between Iranian forces and Kurdish rebels.
This was the most serious incident between the two sides since September.
The report said the Guard clashed Tuesday with armed members of the Party for Free Life in Kurdistan, or PEJAK, which is fighting for greater rights in Iran.
PEJAK is the Iranian wing of the Kurdistan Workers' Party, or PKK, which is struggling for autonomy in Turkey with an eye toward uniting Kurds in the region.
Iran has accused the president of Iraq's semi-autonomous Kurdish region, Massoud Barzani, of providing bases to PEJAK without informing the central Iraqi government in Baghdad. Barzani has not responded publicly to the charge.
Iran has also accused the U.S., Britain and Israel of seeking to incite tension on Iran's borders to undermine the government in Tehran. All three countries have denied that.