For more than four decades, Turkey has been fighting an armed insurgency by the Kurdistan Workers’ Party, or P.K.K., a militant group that says it seeks greater rights for the country’s Kurdish minority.
More than 40,000 people have been killed in decades of conflict, in both P.K.K. attacks on military and civilian targets and Turkish military operations against the militants and the communities that harbor them. Turkey, the United States and other countries consider the group a terrorist organization.
Now, the group’s imprisoned founder, Abdullah Ocalan, has called on Kurdish fighters to lay down their arms and they have declared a cease-fire. It is still unclear, however, whether 40 years of conflict will end and what, if anything, the Turkish government is offering the group in exchange.
Here is what to know about the P.K.K. and its conflict with Turkey.
Who are the P.K.K.?
The group began fighting the Turkish state in the early 1980s, originally seeking independence for the Kurds, who are believed to make up about 15 percent or more of Turkey’s population.
Starting from the mountains in eastern and southern Turkey, P.K.K. fighters attacked Turkish military bases and police stations, prompting harsh government responses. Later, the conflict spread to other parts of the country, with devastating P.K.K. bombings in Turkish cities that killed many civilians.
Over the last decade, the Turkish military has routed P.K.K. forces from major Kurdish cities in southeastern Turkey, while using drones to kill its leaders and fighters, hindering its ability to organize and carry out attacks.
The conflict has been on a low boil for years, although occasional P.K.K. attacks have revived fears of a wider conflict. Last year, a small squad of its militants stormed into the headquarters of a state-run aerospace company armed with rifles and explosives and killed five employees before the security forces regained control.
Who is Abdullah Ocalan?
Mr. Ocalan is the founder and leader of the P.K.K., which has been battling the Turkish state. He has been in a Turkish prison for a quarter century.
Many of Turkey’s Kurds view Mr. Ocalan as a potent symbol of the struggle for Kurdish rights. And despite his imprisonment, he still wields great influence over the P.K.K. and its affiliated militias in Syria, Iraq and Iran.
Mr. Ocalan founded the P.K.K. in the late 1970s with a group of other rebels and largely ran the organization from neighboring Syria as it launched attacks in southeastern Turkey and later in other major Turkish cities.
In 1998, Syria forced him out and he traveled to Greece, Italy and Russia to seek asylum before Turkish intelligence agents, with help from their U.S. counterparts, captured him inside a plane at an airport in Nairobi, Kenya, on Feb. 15, 1999.
After his capture in 1999, he was incarcerated on Imrali Island in the Sea of Marmara, south of Istanbul, where he was the only prisoner for many years.
That same year, Turkey convicted him and sentenced him to death. That sentence was commuted to life imprisonment after Turkey abolished the death penalty as part of its bid to join the European Union.
Since his incarceration, Mr. Ocalan has shifted its ideology away from secession and toward Kurdish rights inside Turkey.
How does Turkey see Mr. Ocalan?
For most Turks, Mr. Ocalan remains the country’s most hated terrorist.
Human rights groups criticized his isolation on Imrali Island. In 2009, five other prisoners were sent to the facility, and Mr. Ocalan was allowed to meet them a few times a week, according to Turkish media reports.
But in recent years, Mr. Ocalan and the island’s other inmates were not allowed any visitors, including their lawyers, or any phone calls with family members.
Last October, a powerful political ally of President Recep Tayyip Erdogan, made a surprising public call to Mr. Ocalan, requesting that he tell his fighters to lay down their arms and end the conflict.
That led to limited visits from relatives and political allies of Mr. Ocalan to explore the possibility of a new peace process between Turkey and the P.K.K.
Who are the Kurds?
The Kurds are an ethnic group of roughly 40 million people — there are widely varying estimates — concentrated in Iran, Iraq, Syria and Turkey.
They speak multiple dialects of Kurdish, a language not directly related to Turkish or Arabic. Most are Sunni Muslims.
The Kurds were promised a nation of their own by world powers after World War I, but that was never granted. There were Kurdish rebellions in various countries over the following generations, and Kurds have faced state suppression of their language and culture.
In Syria, the Kurdish-led Syrian Democratic Forces, whose leaders have roots in the P.K.K. and follow Mr. Ocalan’s ideology, controls the northeastern part of the country. They have been backed for years by the United States and played a crucial role in defeating the Islamic State.
But the fall of the Syrian dictator Bashar al-Assad in December has left their future status unclear. They are clashing with Turkish-backed Syrian Arab rebels, and remain outside of the control of the new Syrian government in Damascus.
Since the 1991 Gulf War, the largely Kurdish northern region of Iraq has been semiautonomous. The P.K.K. leadership is now based in the Qandil Mountains of northern Iraq. In recent years, Turkey has attacked the group and affiliated militias in Iraq and Syria while lobbying the Iraqi government to expel it.
How did previous peace efforts fare?
Multiple efforts to freeze or end the Turkey-P.K.K. conflict have been made, starting with a cease-fire in 1993. But all of them collapsed, often leading to greater bloodshed.
Violence flared on and off until a new round of peace talks began in 2011. At that time, Turkish intelligence officers met with Mr. Ocalan in prison to map out a plan for his fighters to disarm, and Kurdish politicians ferried messages between him and his associates in northern Iraq.
But the process collapsed in mid-2015, with each side blaming the other for the failure. One of the conflict’s most deadly phases followed, with pitched battles in cities in Turkey’s southeast that killed more than 7,000 people, according to the International Crisis Group.
Will this time be different?
Although Turkey still considers the P.K.K. a separatist terrorist group that does not represent the Kurdish people, it has acknowledged some historic violations of Kurdish rights and widened the margins for Kurdish language and culture.
It has licensed Kurdish-language television and radio broadcasts and allowed Kurdish language as an elective course in some schools.
At the same time, however, the government has removed more than 150 elected Kurdish mayors from their posts since 2015, according to the Peoples’ Equality and Democracy Party, which represents the pro-Kurdish movement politically and has seats in Parliament.
Most of the removed mayors were accused, and some convicted, of crimes related to the P.K.K.
Human Rights Watch has called the removal of Kurdish mayors politically motivated and a violation of voters’ rights.
