Three Kurdish women activists - including a co-founder of the PKK - have been found shot dead in a Kurdish information centre in Paris, the BBC reports.
French Interior Minister Manuel Valls called the killings "intolerable".
The three women had "undoubtedly" been executed, Mr Valls said, adding that the French authorities were determined to "shed light on this act".
"In this neighbourhood, in this Kurdish information centre, in the 10th arrondissement [district] where many Kurds live, I also came to express my sympathy to the relatives and close friends of these three women," he said.
Turkey has recently begun talks with the jailed PKK leader Abdullah Ocalan, with the aim of persuading the group to disarm.
However, Turkey is continuing with the mass trial 46 Kurdish and Turkish lawyers for representing the PKK leader.
British lawyers observing the trial said that private conversations between the lawyers and their clients had been ‘routinely’ illegally recorded. See The Guardian’s report.
The PKK, which is fighting for Kurdish self-rule, is listed as a terrorist organization by Turkey, the US and the European Union.
The BBC described the three activists slain Thursday as:
Sakine Cansiz: Founding member of the PKK, and first senior female member of the organisation; while jailed, led Kurdish protest movement out of Diyarbakir prison in Turkey in 1980s; after being released, worked with PKK leader Abdullah Ocalan in Syria; was a commander of the women's guerrilla movement in Kurdish areas of northern Iraq; later took a lower profile and became responsible for the PKK women's movement in Europe
Fidan Dogan: Paris representative of the Brussels-based Kurdistan National Congress (KNC) political group; responsible for lobbying the EU and diplomats on behalf the PKK via the KNC
Leyla Soylemez: Junior activist working on diplomatic relations and as a women's representative on behalf of the PKK