A statement on Saturday by the Kurdistan Workers Party (PKK), carried on the pro-Kurdish Firat news agency, followed a call by its jailed leader Abdullah Ocalan this week for the rebels to implement a cease-fire.
The PKK began its violent campaign to create a Kurdish homeland in the south-east in 1984. More than 30,000 people have died in the conflict, which dwindled after Ocalan was captured and convicted in 1999.
Leading PKK militant Murat Karayilan made the announcement at a news conference in the mountains of northern Iraq, where some 5,000 rebels are based and from where they launch armed raids into neighbouring Turkey.
The move came ahead of an October 2 meeting between Turkish Prime Minister Tayyip Erdogan and U.S. President George W Bush in Washington where the PKK issue is set to be high on the agenda.
Amid mounting military casualties in Turkey, Ankara has warned that it would attack PKK bases in Iraq if US and Iraqi forces failed to act against them.
Erdogan had already dismissed Ocalan's ceasefire offer, saying Kurdish militants had to give up their weapons.
The PKK, considered a terrorist organisation by the European Union, the United States and Turkey, said it would only take up arms in self-defence.