Fighters with a Kurdish separatist militant group that has waged a decades-long insurgency in Turkey began laying down their weapons in a symbolic ceremony on Friday in northern Iraq, the first concrete step toward a promised disarmament as part of a peace process.

Southeast Turkey, where the army has battled Kurdish militants for decades, is not yet convinced that lasting peace is at hand.In a slickly managed ceremony across the border in Iraq Friday, members of the Kurdish rebel group PKK destroyed their weapons as part of a peace process underway with the Turkish state.

The disarmament of the P.K.K., a group that has battled since the 1980s for Kurdish independence, could end a conflict that has killed more than 40,000 people.