Several Turkish soldiers have been killed and others wounded in a major attack in Hakkari province carried out by fighters of the Kurdistan Workers Party (PKK), according to both the Kurdish group and official Turkish media.
There was no immediate official casualty toll but the Turkish military immediately scrambled fighter jets to strike PKK targets after Sunday's ambush in the country's southeast.
The official Anatolia news agency said the attack on two military vehicles in a convoy in Daglica in Hakkari, a known PKK stronghold, had left several soldiers dead and others wounded.
Roadside bombs were detonated as the convoy passed, followed by a gun battle, Al Jazeera's Bernard Smith, reporting from Bodrum, said.
"This seems like a particularly serious attack on the Turkish military since the two and half years ceasefire with the PKK effectively collapsed in mid-June, with both sides blaming each other for the collapse," our correspondent said.
Q&A: Turkey's fight against PKK is 'legitimate'
The PKK described the assault as an "act of sabotage", in a statement posted on the website of its military wing, the People's Defence Forces (HPG).
"An attack from several sides left 15 soldiers dead, and a large amount of weapons were seized in the action," the statement read.
The number of casualties could not be independently verified but in a televised statement Turkish President Recep Tayyip Erdogan confirmed an attack had taken place in Hakkari.
He also indicated that several soldiers were killed in the attack.
Anatolia said Turkish F-4 and F-16 jets were deployed to carry out strikes in retaliation against 12 targets controlled by the PKK.
Many "terrorists" were killed in the air strikes, Anatolia said, without giving a precise toll.
Erdogan reacted to the attack during a live television interview on A Haber channel, saying: "A mine attack has been staged. There will be a very particular and decisive fight there. We are very sad.
"The weather conditions were unfavourable. A struggle was being waged under such conditions."
He said the attack happened during a "clean-up operation" against PKK fighters.
In a sign of the gravity of the attack, Ahmet Davutoglu, Turkey's prime minister, broke off a trip to Konya to watch a national football game and summoned an emergency security meeting in Ankara, Anatolia said.
Davutoglu was taken in his motorcade to attend the security meeting with officials including Hulusi Akar, the army chief of staff, and Hakan Fidan, the spy chief.
The PKK has been staging daily attacks against the Turkish armed forces as the military conducts a sustained operation against the group in southeastern Turkey and northern Iraq.
The violence has shattered a 2013 ceasefire aimed at assisting the search for a final peace deal to end the PKK's three-decade insurgency that has claimed tens of thousands of lives.
|The violence in the southeast comes at a tense time as Turkey prepares to hold snap elections on November 1 [Getty Images]
The PKK initially took up arms in 1984 in search of an independent Kurdish state for Turkey's Kurdish minority, although lately the demands have focused on greater autonomy and rights.
Earlier on Sunday, two Turkish police were killed in an attack in the Sur district of the southeastern city of Diyarbakir that was attributed to the PKK, security sources told AFP news agency.
At least 70 members of the security forces have been killed since July in attacks blamed on the PKK, while official media have claimed that at least 967 fighters have been killed.
The unrest comes at a tense time in Turkey as the country prepares to hold fresh elections on November 1 following June 7 polls where Erdogan's ruling AK party lost its overall majority.
Source: Al Jazeera and agencies