Eleven Turkish police officers were killed Friday in a suicide truck bombing at a security checkpoint in the restive south-eastern town of Cizre, government officials said, blaming the Kurdistan Workers' Party (PKK).
The bombing by the roadblock outside a police headquarters, the latest in a string of explosions in the mostly Kurdish south-east of the country, also injured 75 security force members and three civilians, according to a statement from the local governor.
President Recep Tayyip Erdogan slammed the attack and said it would only increase his country's determination to fight "terrorism," the state-run Anadolu news agency reported.
In a statement on its website, the PKK confirmed that it carried out an action in Cizre against police, but said more information would only be made available on Saturday. The group has claimed similar car bombings on police targets in the past weeks.
Meanwhile, the PKK claimed an attack from Thursday, in north-eastern Atvin province, which killed one soldier and injured two. The attack hit a convoy carrying the leader of the Turkish opposition Republic People's Party (CHP), but the armed group said this was not intended.
"The action was definitively not aimed at the CHP and Kemal Kilicdaroglu," a statement said. "The target of the operation was only the security forces of the Turkish state."
Following the Cizre attack, broadcaster CNN Turk reported that security operations were launched in Sirnak province, located near the borders with Syria and Iraq.
The Turkish broadcasting authority (RTUK) imposed a partial broadcast ban on the attack, as has become normal in Turkey following violent attacks.
Photos that emerged before the ban was imposed showed the police headquarters and a nearby building used by the security forces badly damaged, with entire floors destroyed and black smoke rising from the rubble.
The PKK and the state resumed their conflict last year, after a ceasefire collapsed following the breakdown of peace talks.
At least 1,900 people have died since July last year, including more than 650 members of the security forces, almost half of whom have been killed by improvised explosive devices.
The PKK has confirmed that more than 700 of its members have been killed. At least 320 civilians have also died, according to a database maintained by the International Crisis Group.
More than half a million people have been displaced by heavy fighting in city centres.
The conflict has been ongoing for more than three decades, with the PKK demanding greater autonomy for the Kurdish minority in Turkey, which has long complained of discrimination.
More than 40,000 people have been killed in the conflict. The Turkish government has repeatedly ruled out a return to peace talks despite pressure from Kurdish political groups in the country.
This week, Turkey launched an operation in Syria against Islamic State and Kurdish militants.