"We made an initiative to cease fire for a specific time to start negotiations with the Iranian side, so we can solve the problems between us," Sherzad Kamangar, an Iraq-based spokesman for the Party of Free Life of Kurdistan (PJAK), said by telephone.

He did specify how long the ceasefire would last.

A statement released on PJAK's website on Sunday night said that "if Iran does not agree to the ceasefire, (it) will be responsible for any response" from PJAK fighters, who are based in Iraq's autonomous Kurdistan region.

"The latest events proves that the war will not solve our problems, but rather will increase them and make them deeper," the statement said, adding that the ceasefire would go into effect on Monday at 12:00 pm (0900 GMT).

Iranian state television said Guards had killed 22 PJAK fighters in the offensive it launched in border areas on Friday.

"Twenty-two PJAK rebels were killed in the new Guards operations in Sardasht Heights, and another 27 rebels have been wounded," the report said.

Guards operations officer Colonel Hamid Ahmadi said the offensive would "continue until all counter-revolutionaries, rebels and terrorists have been cleared away."

Iranian media reported on Saturday that two Guards had been killed on the first day of the offensive.

PJAK rebels have clashed repeatedly with Iranian forces in recent years, drawing retaliatory bombing of their rear-bases in mountainous border districts of Iraqi Kurdistan.

In July, Iran launched a major offensive against the rebels, shelling border districts for weeks.

Commanders said they had halted operations during the Muslim fasting month of Ramadan to give the rebels a chance to pull back from border areas but they had failed to do so.

Human Rights Watch said on Friday that it had evidence that Iran may have deliberately targeted civilians in its offenisve against the rebels.

It accused Turkey too of failing to take adequate precautions to protect civilians in its campaign of shelling and air raids against suspected rear-bases in northern Iraq of the rebel Kurdistan Workers' Party (PKK).

Ankara announced the resumption of operations against PKK rear-bases in mid-August. The group has been fighting for Kurdish self-rule in southeastern Turkey since 1984.