A co-founder of the Kurdistan Workers' Party (PKK) and two other militants were found shot dead Thursday in Paris, a day after Turkey and the jailed leader of the banned group were reported to have agreed on a peace plan to end a three-decade-old insurgency.
Riot police maintained order as hundreds of angry Kurds rushed to protest and chant "We are all PKK!" outside the Kurdistan Information Centre in the city's 10th district where the victims were found shot in the head and neck.
Interior Minister Manuel Valls described the killings as assassinations.
"Three women have been shot down, killed, without doubt executed," he told reporters.
Experts on the Kurdish movement said the killings could be the result of internal feuding in the PKK, personal score-settling, the work of Turkish agents or even of Turkish far-right extremists.
Kurdish activists protesting in Paris were adamant they must have been the work of Turkish agents, while Turkish officials suggested internal PKK divisions were a more likely explanation.
Turkish Prime Minister Recep Tayyip Erdogan said it was "too soon to comment" but the incident could be a "provocation", coming at a time when peace talks between the state and the PKK's jailed leader Abdullah Ocalan were under way.
Turkish media reported Wednesday that the Turkish government and Ocalan had agreed on a roadmap to end the insurgency that has claimed around the lives of 45,000 people, most of them Kurds.
The PKK, listed as a terrorist organisation by Turkey and by much of the international community, has been fighting for Kurdish autonomy or independence in southeastern Turkey since 1984.
One of the dead in the Paris centre was Sakine Cansiz, a founding member of the PKK considered close to Ocalan.
A US embassy report from April 2007 revealed on the Wikileaks website said that "US and Turkish officials had identified Cansiz as a priority PKK leader to bring to justice".
She was arrested in Hamburg the same year but released after the German courts refused to extradite her to Turkey.
The second slain woman in Paris was 32-year-old Fidan Dogan, an employee of the centre, who was also the Paris representative of the Brussels-based Kurdistan National Congress.
The third was Leyla Soylemez, described by the federation as a "young activist".
The three were last seen alive midday on Wednesday at the centre on the first floor of a building on Rue Lafayette, according to the centre's director, Leon Edart.
Friends and colleagues who tried and failed to contact them eventually went to the centre and found traces of blood on the door, which they then forced open to find the three bodies inside around 01:00 am Thursday, said Edart.
Two of the women were shot in the nape of the neck while the third had wounds to her forehead and stomach, the Kurdish federation said.
There are around 150,000 Kurds in France, the vast majority of them of Turkish origin.
French police in October detained a suspected European leader of the PKK and three other members of the group as part of a probe into terrorism financing and association with a terrorist group.
Turkish Prime Minister Erdogan in September accused France and Germany of obstructing Ankara's fight against the PKK.
The PKK raises funds through a "revolutionary tax" on Kurdish expatriates that authorities in several countries have condemned as extortion. Several PKK leaders have also been designated as drugs traffickers by the United States.
Erdogan's government recently revealed that Turkish intelligence services had for weeks been talking to Ocalan, who has been held on the island prison of Imrali south of Istanbul since his capture in 1999.
Under the reported peace roadmap, the government would reward a ceasefire by granting wider rights to Turkey's Kurdish minority, whose population is estimated at up to 15 million in the 75-million nation.
The rebels also reportedly want the release of hundreds of Kurdish activists and the recognition of Kurdish identity in Turkey's new constitution.
Such a deal would be controversial, both among hardline Turkish nationalists and sections of the PKK opposed to any compromise with Ankara, analysts say.