Members of the Kurdish security force in the autonomous north of Iraq told AFP sustained fighting continued unabated since late Sunday as troops, backed by artillery and air cover, fought to seize a main rebel camp in the Zap area.
The camp, situated in a deep valley just a six-kilometre walk from the Turkish border, is one of the main passages used by Kurdistan Workers' Party (PKK) rebels to infiltrate Turkish territory for attacks.
Clashes also continued since late Monday in the mountainous Hakurk area to the east, close to Iraq's border with Iran, where the Turkish army air-dropped troops and helicopter gunships pounded rebel positions, the sources said.
The fighting came a day after Turkish jets bombed Hakurk, a prominent PKK stronghold some 20 kilometres from the Turkish frontier.
Turkish troops crossed into northern Iraq Thursday evening in the largest cross-border offensive in years against PKK hideouts in the region, bombing rebel positions and fighting the militants on the ground.
The Turkish army said Monday that it killed 153 PKK rebels and lost 17 soldiers since the beginning of the incursion.
At the weekend, the Iraqi government urged Turkey to withdraw its forces "as soon as possible", while the White House also said it hoped the Turkish incursion would be short-lived and would avoid harming civilians.
Ankara says an estimated 4,000 PKK rebels holed up in northern Iraq use the region as a springboard for attacks on Turkish territory as part of their campaign for self-rule in Kurdish-majority southeast Turkey.
The conflict has claimed more than 37,000 lives since the PKK, listed as a terrorist group by Ankara and much of the international community, took up arms in 1984. (AFP)
Fierce fighting as Turkish troops move on rebel camp in Iraq