Turkish warplanes killed 23 Kurdish villagers in an air strike near the Iraqi border Thursday when smugglers were apparently mistaken for PKK militants, a pro-Kurdish official said.
Provincial officials found 23 bodies at Ortasu village in Sirnak province, said Ertan Eris, a local councillor of the pro-Kurdish Peace and Democracy Party (BPD).
Local security sources said the dead were among a group smuggling gas and sugar into Turkey from northern Iraq and may have been mistaken for Kurdistan Workers' Party (PKK) rebels.
Sirnak governor Vahdettin Ozkan said an investigation was under way into what he described as an "incident" in which more than 20 people had been killed.
"A crisis centre has been set up in the area and prosecutors and security officers have been sent there," Ozkan said.
Eris told pro-Kurdish Roj TV from the bombing site that the dead were among a group of up to 40 people, ranging in age from 16 to 20, who were engaged in smuggling. He said the death toll was likely to rise further, as snow and rough terrain was complicating the search for bodies.
The pro-Kurdish Firat news agency said 35 villagers, including children, were killed in the strikes. The agency released photos showing bodies wrapped in blankets, lying on the snow side by side.
Kurdish media and local sources close to the PKK have presented slain rebels as civilians after previous incidents in the area, where the militants are known to operate.
The PKK took up arms in Kurdish-majority southeastern Turkey in 1984, sparking a conflict that has claimed about 45,000 lives. It is labelled a terrorist organisation by Ankara and much of the international community.
Clashes between Kurdish rebels and the army have escalated in recent months.
The Turkish military launched an operation on militant bases inside northern Iraq in October after a PKK attack killed 24 soldiers in the border town of Cukurca, the army's biggest loss since 1993.
The army then killed 36 Kurdish rebels in Kazan Valley in Hakkari province, near the Iraqi border.
Media reports in Turkey and abroad, as well as the BDP, have accused Turkey of using chemical weapons against the rebels, allegations strongly denied by the military.
Iraqi officials and the BDP in August claimed Turkish warplanes killed a family of seven in northern Iraq during an operation to bomb PKK bases.
Turkey denied the charges and summoned Iraq's ambassador to protest the claims. An anonymous Turkish diplomat called the allegations "a PKK game".
In November Turkey bombed the Sulaimaniyah and Arbil provinces of Iraq's autonomous northern Kurdish region, wounding a civilian, Kurdish officials said.