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.

The disarmament process will start under tight security in Iraqi Kurdistan and is expected to take all summer.

The Kurdistan Workers’ Party (PKK) has begun the first steps towards disarmament, closing a chapter on a four-decade armed campaign against the Turkish state in a conflict that has killed more than 40,