Two Turkish policemen and seven Islamic State (IS) suspects have been killed in a shoot-out that has further rattled the increasingly polarised country just six days ahead of snap elections.
Police are hunting down IS militants after suicide bombings that killed 102 people at a pro-Kurdish peace rally in the heart of the capital Ankara on October 10, the worst attack in Turkey's modern history.
Monday's (local time) gun battle in the main southeastern Kurdish city of Diyarbakir was the first on Turkish soil between security forces and the jihadists since Ankara launched air strikes on IS targets in Syria in July.
Fears of further bloodshed have overshadowed the run-up to Sunday's vote, with an IS cell reportedly plotting major attacks, while Kurdish rebels have taken up arms again after the collapse of the peace process.
A police anti-terrorist squad launched dawn raids on several houses in Diyarbakir where militants were thought to be hiding out.
The suspects opened fire and set off booby trap bombs, killing two police officers and injuring five, according to the Diyarbakir governor's office.
Seven IS militants were killed and 12 arrested after at least two hours of heavy fighting, it said.
"This was an important operation... we can say we have neutralised a major Daesh cell," Deputy Prime Minister Numan Kurtulmus told reporters, using an Arabic name for the IS group.
The authorities declared the IS group the number one suspect over the Ankara bombings, but many accuse them of security failings and of turning a blind eye to the jihadists fighting the Damascus regime.
President Recep Tayyip Erdogan himself has vowed to fight all Turkey's "enemies" as his Justice and Development Party (AKP) battles to regain the parliamentary majority it lost in June's election, ending 13 years of single party rule.
He said on Monday that Turkey would press on with its operations against "terrorists" before and after Sunday's vote, saying it makes no distinction between the PKK, the Islamic State and the DHKP-C, an outlawed Marxist group.
A massive police hunt was also under way at the weekend for a suspected IS cell that included a German woman allegedly plotting to carry out other attacks, Turkish media reported.
The Anatolia news agency said security forces feared they were preparing a major strike "such as hijacking a plane or a vessel or detonating suicide bombs in a crowded location".