Turkey says its troops have killed 15 Kurdish rebels during a major operation in eastern Turkey.

Military officials say the Turkish air force supported ground troops during the fighting Sunday. The scene was a mostly Kurdish province, Tunceli, over 300 kilometers from the Iraqi border region where most other recent violence has occurred.

No information about government casualties is available.

Separately, an explosion in the western city of Izmit, in Kocaeli province, injured three people protesting violence by Kurdish separatists.

Turkey's foreign minister says all options are still open in the fight against Kurdish rebels and terrorists based in northern Iraq.

Ali Babacan spoke during a visit to Iran on Sunday to thank authorities for their help in combating the Kurdistan Workers' Party (PKK), and to discuss other aspects of Turkish-Iranian cooperation.

Babacan met with Iran's foreign minister, Manouchehr Mottaki, who contends the United States and Israel support some Kurdish terrorist activities.

Ankara is threatening a full-scale military incursion into northern Iraq in pursuit of PKK fighters who killed 13 Turkish soldiers on October 21, during a cross-border raid in southeastern Turkey. So far, Turkey has amassed tens of thousands of troops along its border with Iraq, and it has carried out some air and artillery strikes against rebel targets.

Turkey has rejected assurances from Baghdad that Iraqi authorities will restrict PKK operations in their northern territory.

Iranian President Mahmoud Ahmadinejad strongly criticized the PKK in a telephone conversation with Turkish President Abdullah Gul. According to state-run media in Tehran, Mr. Ahmadinejad says terrorist activities by the PKK are harming the interests of Turkey, Iran and Iraq.

The office of Iraqi Prime Minister Nouri al-Maliki says he also discussed the PKK issue with Iran's president in a telephone conversation. Mr. Maliki's office says the two leaders agree on the need to confront PKK violence, but that they prefer to solve the crisis peacefully.

The European Union and the United States are pressing Ankara to refrain from invading northern Iraq.

Since the PKK began its active campaign for Kurdish autonomy in southeastern Turkey, more than 20 years ago, fighting and other violence has killed more than 30,000 people.