Turkey's military says 13 soldiers have died in a helicopter crash near the border with Iraq.
A military statement said the AS532 Cougar helicopter crashed on Wednesday shortly after taking off from a base in the region of Senoba in Sirnak province.
"As a result of the painful accident, our hero comrades in the helicopter fell as martrys," the statement said.
It said initial information indicated that the helicopter hit a high-voltage transmission line.
The governor's office for the province of Sirnak said the helicopter crashed near the town of Uludere, three minutes after taking off.
The helicopter crashed at 8:55 pm (1755 GMT), the military said, adding that an investigation was underway.
Turkey's chief of staff, General Hulusi Akar, travelled to the region to carry out an inspection, the state-run Anadolu news agency reported.
Deputy Prime Minister Mehmet Simsek, Defence Minister Fikri Isik and Interior Minister Suleyman Soylu were also travelling to the region, it added.
President Recep Tayyip Erdogan was reportedly briefed about the accident after chairing the country's top National Security Council meeting in Ankara
The crash occurred as Turkish troops are engaged in operations against Kurdish fighters in a mountainous region of Sirnak province.
In March, seven people, including four Russians, were killed when a privately owned helicopter crashed in Istanbul after hitting a television tower.