ISTANBUL: The execution-style killing in Paris of three Kurdish female activists, including a founder of the PKK militant group, appears to have been the result of an internal feud, Turkish Prime Minister Tayyip Erdogan said on Friday.

Sakine Cansiz, a founding member of the Kurdistan Workers' Party (PKK), and two fellow activists were found shot in the head early on Thursday in an attack which overshadowed peace moves between Turkey and the guerrillas.

Erdogan said that while investigations needed to be completed before a definitive conclusion could be reached, evidence so far pointed to an inside job, as the building was secured by a coded lock which could only be opened by insiders.

"Those three people opened it. No doubt they wouldn't open it to people they didn't know," Erdogan told reporters on his plane returning from Senegal on Friday, according to the state-run Anatolian news agency.

He said the killings could also have been intended to sabotage efforts towards peace talks with the PKK.

Cansiz was a prominent PKK figure, initially as a fighter and later in charge of the group's civil affairs in Europe, according to a Kurdish lawyer who knew her. A 1995 photograph shows her standing next to militant leader Abdullah Ocalan, wearing olive battle fatigues and clutching an assault rifle.

French investigators gave no immediate indication of who might be behind the murders. The PKK has seen intermittent internal feuding during an armed campaign in the mountainous Turkish southeast that has killed some 40,000 people since 1984.

Turkish nationalist militants have in the past also been accused of killing Kurdish activists, who want regional autonomy. But such incidents have been confined to Turkey.

Turkey recently announced it had begun talks with Ocalan, jailed on the small island of Imrali near Istanbul. Hardliners in the PKK, deemed a terrorist group by Ankara, Washington and the European Union, are likely to be sceptical about such talks.

According to media reports, the Turkish state and PKK have agreed the framework for a peace plan, which would involve boosting Kurdish minority rights in exchange for the ultimate disarmament of the militants.

Erdogan has introduced reforms allowing Kurdish language broadcasting and other concessions on language; but activists are demanding more freedom in education and administration.

Kurdish politicians are also demanding improved prison conditions for Ocalan with a view to him being released from jail and put under house arrest, but Erdogan played down any changes in Ocalan's situation.

"The conditions at Imrali are better than those in any country in the world and we're talking about special treatment," Erdogan said. Ocalan was able to walk daily in a courtyard with other inmates and would be given a television, he said.