Turkish troops have killed 15 suspected Kurdish rebels in the east of the country, reports say.
Turkey has massed about 100,000 troops near the Iraq border
Military sources and Turkish TV reports said operations were taking place near the town of Pulumur, in the eastern province of Tunceli.
The area is thought to be a stronghold of separatists from the Kurdistan Workers' Party (PKK).
Turkey has stepped up moves against the PKK recently after strikes from across the border with Iraq.
The government in Ankara has warned it will not tolerate continued raids by PKK fighters based in northern Iraq, and has massed troops near the border in preparation for a possible ground invasion.
Sunday's raid happened a considerable distance from the border flashpoints.
Tunceli is some 550km (340 miles) north-east of the province of Sirnak and 650km (400 miles) north-east of Hakkari, where most of the recent fighting has taken place.
The government-run Anatolia news agency said fighting began on Sunday morning, with Turkish troops backed by helicopter gunships.
One report said some 8,000 troops were involved.
Security forces also shut down a major highway leading to the town of Pulumur, Anatolia reported.
There was no official confirmation of casualty figures, but two private TV stations said 15 PKK rebels were killed.
The latest raid came a day after Turkish Prime Minister Recep Tayyip Erdogan criticised European Union nations for not doing enough to rein in the guerrillas.
He said EU nations were not arresting or extraditing PKK members.
Formed in late 1970s
Launched armed struggle in 1984
Dropped independence demands in 1990s
Wants greater autonomy for Turkey's Kurds
Leader Abdullah Ocalan arrested in 1999
Ended five-year ceasefire in 2004
Called a terrorist organisation by Turkey, the EU and US
Turkey has demanded that Iraq hand over any PKK members based in northern Iraq, something the leader of the semi-autonomous Kurdish Regional Government has refused to do.
Speaking to al-Jazeera TV, Masoud Barzani also said he would not allow the PKK to use the region as a base for attacks on Turkey.
There were a number of anti-PKK demonstrations across Turkey over the weekend, with fresh protests in Istanbul on Sunday.