Turkish fighter jets have bombed several Kurdish PKK rebel positions on the border with Iraq, according to the semi-official Anatolia news agency.
Turkey has been building up its military presence on the border
Fighter jets reportedly destroyed mountain bases in the Turkish provinces of Sirnak, Hakkiri, Siirt and Van, and bombed mountain paths used by fighters.
The raids follow an attack by PKK rebels on Sunday in which 12 Turkish soldiers were killed.
The Turkish military says eight soldiers are missing.
Several F-16 warplanes loaded with bombs and attack helicopters took off from an air base in south-eastern city of Diyarbakir, an Associated Press cameraman reported.
They bombed mountain paths used by rebels to cross from Iraq into Turkey, Anatolia said.
Intense diplomatic efforts are continuing to persuade Turkey against launching a possible ground offensive into northern Iraq to target PKK bases there.
US officials have warned against escalating tensions between Iraq and Turkey, and called for restraint.
"We are concerned about the continuing skirmishes that are happening up there, and terrorist attacks that are being launched by the PKK against the Turks," White House spokeswoman Dana Perino said.
The president of Iraq's autonomous Kurdish region, Massoud Barzani, has urged the PKK to abandon violence in its campaign for greater rights for Kurds in Turkey.
"We do not accept in any way... the use of Iraqi territories, including the territories of the Kurdistan region, as a base to threaten the security of neighbouring countries," Mr Barzani said.
A Turkish government official confirmed that Turkish artillery units shelled rebel positions on Tuesday night but refused to give further information.
Earlier Hurriyet newspaper quoted Deputy Prime Minister Cemil Cicek as saying that Turkish F-16 bombers had flown at least 20km (12.4 miles) into Iraqi territory on Sunday and struck guerrilla training camps.
Other Turkish officials later denied the reports.
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
Turkey's political and military leaders have met to discuss the details of a possible offensive into northern Iraq against the PKK rebels.
A high level delegation from Iraq is expected to visit Ankara on Thursday.
Iraqi Prime Minister Nouri Maliki said on Tuesday he would work to limit the PKK's activities, adding that the group's offices in Iraq would be closed.
In the past week, Turkey has been building up its military presence on the border with Iraq, while PKK rebels have stepped up their attacks against Turkish troops.
There are thought to be about 3,000 PKK rebels based in Iraq. They have been blamed for a number of cross-border raids.
Turkish leaders have come under intense pressure from the public and the media to use force.
Foreign Minister Ali Babacan said on Tuesday that Turkey would put an emphasis on a diplomatic solution, but rejected a ceasefire with the rebels.
Turkey, along with the US and EU, describes the PKK as a terrorist organisation.