Surge in violence
The fighting erupted after PKK rebels, armed with rockets and assault rifles, attacked a military unit in a rural area in Siirt province.
The PKK, which has stepped up violence in recent weeks, takes refuge in bases in northern Iraq, using them as a launching pad for attacks on Turkish targets across the border.
Violence surged after Abdullah Ocalan, the jailed PKK leader, said through his lawyers in May that he was abandoning efforts to seek dialogue with Ankara for a peaceful end to the 26-year conflict.
The mounting clashes dealt a severe blow to an already faltering government initiative, announced last year, to boost Kurdish freedoms and investment in the impoverished southeast, in a bid to cajole the PKK into laying down arms.
The Turkish army has been targeting PKK hideouts in northern Iraq under a parliamentary authorisation for cross-border military action, which was first approved in 2007 and later extended until October.
The surging violence has cast a shadow also on Turkish efforts to mend fences with the Iraqi Kurds, whom Ankara had often accused in the past of tolerating the PKK in their autonomous region in northern Iraq.
The PKK, listed as a terrorist group by Ankara and much of the international community, took up arms for Kurdish self-rule in the southeast in 1984, sparking a conflict that has claimed more than 40,000 lives.