Outlawed Kurdish group the PKK, which has waged a 40-year insurgency against Turkey, has announced it is laying down its arms and disbanding.

The Kurdistan Workers’ Party, or PKK, has formally declared its dissolution on Monday, marking a historic milestone that could bring an end to one of the world’s longest-running conflicts. For decades, the insurgency has extended beyond Turkey’s borders into northern Iraq and northern Syria, claiming tens of thousands of lives.

In its statement, the PKK said, according to a Reuters report, it "has completed its historic mission," which over the years shifted to seeking greater Kurdish rights and limited autonomy in southeast Turkey, rather than an independent state.