The Kurdistan Workers Party (PKK) has claimed a deadly suicide bomb attack on Turkish police in the southeastern town of Cizre that left 11 officers dead and wounded dozens more.
Large plumes of smoke billowed from the site in Cizre, located in Turkey's Sirnak province bordering both Syria and Iraq, footage on CNN Turk showed.
The broadcaster said a dozen ambulances and two helicopters had been sent to the scene.
Photographs broadcast by private channel NTV showed a large three-storey building reduced to its concrete shell, with no walls or windows, and surrounded by grey rubble.
"Our sacrifice team staged a comprehensive action in Cizre that left dozens of police dead," said the PKK, which is known for exaggerating tolls.
In the statement on its website it said the attack was retaliation for the "continued isolation" of its jailed leader Abdullah Ocalan and the "lack of information" about his welfare.
Ocalan is held on the prison island of Imrali off Istanbul but has not been allowed visits by lawyers or supporters for over a year.
The PKK also said it was behind an attack yesterday in the northeastern province of Artvin on a convoy carrying the leader of the main opposition Republican People's Party (CHP) Kemal Kilicdaroglu.
The PKK denied targeting the politician, saying it had "no advance information" he was in the convoy.
One gendarme was killed in the attack.
The attack was presented by some politicians as an assassination attempt against Mr Kilicdaroglu and an attack on democracy in Turkey.
Mr Kilicdaroglu was unharmed and attended the funeral of the dead gendarme today.
Turkish special forces, tanks and warplanes launched their first major incursion into Syria on Wednesday in support of Syrian rebels, in an operation President Tayyip Erdogan has said is aimed both at driving Islamic State away from the border area and preventing territorial gains by the Kurdish YPG militia.
Turkey views the YPG as an extension of the PKK, which is listed as a terrorist organisation by Turkey, the United States and the European Union.
More than 40,000 people, mostly Kurds, have died since the rebels took up arms in Turkey in 1984.
Turkish troops fired on YPG fighters in northern Syria yesterday.
