A Kurdish militia group that has waged a bloody insurgency against the Turkish state for four decades said on Monday that it would lay down its arms and disband, a decision that could reshape Turkish politics and reverberate in neighboring countries.

The announcement by the Kurdistan Workers’ Party, known by its Kurdish acronym, P.K.K., came a few months after its imprisoned leader, Abdullah Ocalan, urged the group to disarm and disband. In his February message, he said the group’s armed struggle had outlived its initial purpose and that further progress in the struggle for Kurdish rights could be achieved through politics.

The P.K.K. began as a secessionist group that sought to create an independent state for Turkey’s Kurdish minority. More recently, it has said that it sought greater rights for Kurds inside Turkey. It is classified as a terrorist organization by Turkey, the United States and other countries.

In a statement on Monday, the group echoed Mr. Ocalan’s call, saying that it had “carried the Kurdish issue to a level where it can be solved by democratic politics, and the P.K.K. has completed its mission in that sense.”

A recent congress by the group’s leaders in northern Iraq had decided to end “the work under the name of P.K.K.’’