| DIYARBAKIR, Turkey
DIYARBAKIR, Turkey Turkish soldiers have killed 18 Kurdish rebels in two days in an offensive involving over 2,000 troops, as well as by F-16 fighter jets operating on both sides of the Turkey-Iraq border, security sources said on Friday.
The operation against separatist rebels from the Kurdistan Workers' Party (PKK) began on Wednesday night in Sirnak, a southeasterly province bordering Iraq and Syria and the site of frequent clashes between rebels and Turkish troops.
The summer has been one of the bloodiest in Turkey since the PKK took up arms against the state in 1984 with the aim of carving out a Kurdish state.
"Eighteen PKK members have been killed. The intense operation is continuing," security sources told Reuters.
The operation has largely focused on Kato mountain, a remote area in Sirnak, but Turkish security sources as well as Iraqi residents said warplanes had bombed areas inside northern Iraq's semi-autonomous Kurdistan region.
A Reuters witness said he had seen several F-16 jets take off from Diyarbakir air base on Thursday night and Friday morning. Diyarbakir is the main city in Turkey's predominantly Kurdish southeast.
There were no reports that Turkish ground troops had crossed the border into northern Iraq, although Turkey has sent soldiers into the region in the past, and still has some 1,000 troops based there under an agreement with Iraq dating from the 1990s.
PKK ATTACKS ON THE RISE
Turkey has stepped up air operations on suspected PKK rebels in northern Iraq over the past year after an increase in PKK attacks, and the raids have fuelled tension between Ankara and the Kurdistan Regional Government (KRG).
Security sources said one Turkish soldier had been killed during clashes with PKK militants at the start of the offensive on Wednesday night.
On Sunday, PKK fighters killed 10 members of Turkey's security services in simultaneous attacks on four state and security installations in Sirnak.
More than 40,000 people have been killed since the start of the conflict between the Turkish state and the PKK, which is considered a terrorist organization by Turkey, the United States and the European Union.
In the 15 months to August, some 800 people were killed, including about 500 PKK fighters, more than 200 security personnel and about 85 civilians, according to estimates by the International Crisis Group think-tank.
Ankara has linked the upsurge on the unrest in neighboring Syria and Prime Minister Tayyip Erdogan has accused Syria's President Bashar al-Assad of arming the PKK militants.
Turkey has raised the possibility of military intervention in Syria if the PKK were to launch attacks from Syrian soil. On Wednesday, the military conducted a major military exercise on the Syrian border, a clear warning to Damascus.
(Writing by Jonathon Burch; Editing by Kevin Liffey)