A Kurdish militant group announced a historic decision Monday to disband and disarm as part of a new peace initiative with Turkey, after four decades of armed conflict.

The decision by the Kurdistan Workers’ Party, or PKK, was announced by the Firat News Agency, a media outlet close to the group. It comes days after it convened a party congress in northern Iraq.

In February, PKK leader Abdullah Ocalan, who has been imprisoned on an island near Istanbul since 1999, urged his group to convene a congress and formally decide to disband, marking a pivotal step toward ending the decades-long conflict that has claimed tens of thousands of lives since the 1980s.

On March 1, the PKK announced a unilateral ceasefire, but attached conditions, including the creation of a legal framework for peace negotiations.

The group has led an armed insurgency since 1984 that has left claimed tens of thousands of lives. It is listed as a terror group by Turkey and its Western allies.