Abdullah Ocalan, the jailed leader of the Kurdistan Workers' Party (PKK), has urged the group to establish a congress on ending its three-decade armed struggle against the Turkish state.
In a message relayed by Kurdish politicians to tens of thousands of supporters celebrating a spring festival in the southeastern city of Diyarbakir, Ocalan said the PKK should convene a congress to decide to abandon arms and seek a democratic solution.
He also suggested that the Turkish government should take democratic steps outlined in a vague 10-point declaration that both sides have agreed on.
Ocalan called for the establishment of committees to oversee the peace process and help the sides confront their violent past.
"As the principles of the declaration are agreed upon, I see it as essential and historic that the PKK holds a congress to ... bring an end the roughly 40-year armed struggle against the Republic of Turkey," he said.
The 66-year-old said that the longstanding conflict with Turkey had become "unsustainable", and called for moves towards a peaceful resolution to a violence that has killed tens of thousands of people since 1984.
"This struggle of our 40-year-old movement, which has been filled with pain, has not gone to waste but at the same time has become unsustainable," Ocalan said in the message, read out at a rally to mark the Kurdish "Newroz" New Year celebrations.
"History and our people are demanding from us a democratic solution and peace in line with the spirit of the age," he said, calling for the congress to determine the PKK's "political and social strategy in harmony with the spirit of the new period".
'Digging a pit for Turkey'
Large screens each side of a stage showed Ocalan's face while many waved the flags of his group, deemed a terrorist organisation by Ankara, the United States and the European Union.
President Tayyip Erdogan, then prime minister, launched talks with Ocalan in late 2012 to end the fighting which has ravaged the region's economy and tarnished Turkey's image abroad.
Progress has been faltering since then, but Kurdish faith in Ocalan, who was captured in 1999, remains undiminished.
Devlet Bahceli, leader of the nationalist MHP opposition, has accused Erdogan's AK party and the PKK of "digging a pit for Turkey".
"Kurds are using this day, Newroz, as an occasion to challenge the state," he said.
"Those traitors who are throwing Turkey's future to the fire will be burned in that fire ... Don't test our patience and our love of this nation."
The peace efforts have also revealed tensions between Erdogan, who seeks executive powers as president but does not constitutionally have them, and the government.
In unusually direct criticism, Deputy Prime Minister Bulent Arinc accused Erdogan of being "emotional" and of meddling in government business after he said he did not agree with the establishment of a committee to monitor the peace process, a step agreed with Kurdish politicians.
"It is the government which is running the country," he told reporters. "The president speaking like this, to the point of criticising our government, may wear out the government."