Police raided a house used by the extremists in Diyarbakir city yesterday, triggering a clash that left the two policemen and seven IS militants dead.
About 15 suspected militants were detained and the government labelled the raid as an important blow to an IS cell in Turkey.
Authorities initially said the officers died from booby-trap bombs while breaking down the door.
But a statement released today by the region's governor's office said: "Two policemen were martyred and five security force members were injured during the operation as a result of a suicide bomber blowing himself (or herself) up."
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It was not clear if he or she was among a group of suspects which police have named as possible suicide attackers planning to carry out bombings in Turkey.
Turkey stepped up operations against the IS extremist group following two suicide bombings of a peace rally in Ankara on October 10, which killed 102 people.
The government came under intense criticism for failing to prevent the attack and media reports have said one of the bombers was known to authorities as a possible suicide attacker.
Today, police detained some 30 IS suspects in raids in the central Turkish city of Konya and in the nearby town of Cumra, while a further 21 people were detained in Istanbul, the state-run Anadolu Agency reported.