At least 11 police officers have been killed and 70 wounded in a truck bomb attack at a police headquarters in Cizre in southeastern Turkey, according to the local governor's office.
The bomb was exploded at a checkpoint outside the headquarters on Friday, after the attackers failed to pass the guards there, state media said. The blast was followed by an armed battle between the police and attackers.
Predominantly-Kurdish Cizre is in Turkey's Sirnak province and it borders both Syria and Iraq.
The attack killed 11 police officers and injured 78 people, 3 of whom were civilians, the statement by Sirnak governor's office said.
Large plumes of smoke billowed from the attack site, footage on Turkish televisions showed. They also displayed a large three-storey building reduced to its concrete shell, with no walls or windows, and surrounded by grey rubble.
PKK claims responsibility
The outlawed Kurdistan Workers' Party (PKK) rebels claimed responsibility for Friday's attack.
"Our sacrifice team staged a comprehensive action 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 more than a year.
The PKK also said it did not deliberately target the leader of Turkey's main opposition party in an attack in the northeast on Thursday.
The government had said the PKK had targeted the convoy of Kemal Kilicdaroglu, leader of the secularist Republican People's Party (CHP), who escaped unharmed. One security official was killed in the incident.
"We will give those vile [attackers] the answer they deserve," Prime Minister Binali Yildirim told a news conference in Istanbul on Friday.
The PKK, an armed group seen as a terrorist organisation by Turkey, the US and the EU, has recently stepped up its attacks in southeastern Turkey.
INTERACTIVE: Timeline of attacks in Turkey
The latest attack in Cizre comes two days after Turkish forces launched an unprecedented ground and air offensive into neighbouring Syria, which, according to Turkish officials, targeted the Islamic State of Iraq and the Levant (ISIL) and Syrian Kurdish fighters.
Ankara sees Syria's Kurdish Democratic Union Party (PYD) and its armed People's Protection Units (YPG) fighters as an extension of the PKK.
Southeastern Turkey is going through the most intense fighting in decades after a ceasefire between the Turkish state and the PKK collapsed in July last year.
The military has repeatedly ordered military operations and curfews in southeastern urban centres, including Cizre, since then.
More than 40,000 people, have died since the PKK rebels took up arms in 1984.
Source: Al Jazeera News and agencies