Abdullah Ocalan, the imprisoned Kurdish leader, called on his militant group on Thursday to lay down its arms and dissolve as part of a new bid to end a four-decade long conflict that has claimed tens of thousands of lives.

The founder of the P.K.K., a guerrilla organization that has been fighting an insurgency against Turkey for decades, has called for his group to disarm and disband.

Abdullah Ocalan, the Kurdish militant leader jailed by Turkey who called on Thursday for his Kurdistan Workers Party (PKK) to dissolve and all groups to lay down arms, is an influential figure among the main Kurdish groups in northeastern Syria.