* PKK involved in almost daily clashes for about a year
* Turkey battling Kurdish militia, Islamic state in Syria
A car bomb at a police headquarters in Turkey's largely Kurdish southeast killed at least 11 and wounded dozens on Friday, ministers said, two days after Turkey launched an incursion against Islamic State and Kurdish militia fighters in Syria.
The state-run Anadolu news agency blamed the attack on the Kurdistan Workers Party (PKK), a militant group which has waged a three-decade insurgency for Kurdish autonomy and has been involved in almost daily clashes with security forces since a ceasefire collapsed more than a year ago.
There was no immediate claim of responsibility.
The bombing, the latest in a series of attacks in the southeast, comes as Turkey tries to recover from a failed July 15 military coup.
More than 1,700 military personnel have been removed for their alleged role in the putsch, including some 40 percent of admirals and generals, raising concern about the NATO member's ability to protect itself as it battles both Islamic State in Syria and Kurdish militants at home.
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.
Economy Minister Nihat Zeybekci, speaking on broadcaster NTV, said 11 police officers were killed and 78 were wounded. Health Minister Recep Akdag said four of them were critical.
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.
Deputy Prime Minister Numan Kurtulmus tweeted that Islamic State, the PKK and Syrian Kurdish YPG militia were attacking Turkey to take advantage of last month's coup attempt, although he did not specifically refer to the Cizre attack.
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 YPG.
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 U.S.-backed YPG fighters in northern Syria on Thursday - a confrontation that highlights the cross-cutting of interests of two pivotal NATO allies.
Also on Thursday, Interior Minister Efkan Ala accused the PKK of attacking a convoy carrying the country's main opposition party leader, Kemal Kilicdaroglu.
The government has blamed the PKK for a series of attacks this month in the southeast. The group has claimed responsibility for at least one attack on a police station.
Last week Erdogan accused followers of a U.S.-based Islamic cleric he blames for the July 15 coup attempt of being complicit in attacks by Kurdish militants.
The cleric, Fethullah Gulen, has denied any involvement in and denounced the coup plot.