The defence ministry said the accident occurred when a heavy artillery shell exploded at a base at Sungu Tepe in southeastern Turkey near the borders with Iraq and Iran on Friday.

"We have seven martyrs in the munitions depot explosion... and also we have 25 wounded," Erdogan told a press conference.

He said investigations were under way to find out exactly what happened. Both Defence Minister Hulusi Akar and armed forces chief Yasar Gulu went to the remote depot located in the mountains.

Turkey's predominantly Kurdish southeast has seen years of fighting between the army and the Kurdistan Workers' Party (PKK), classified a "terrorist" group by Ankara and its Western allies.

Turkey also regularly bombs PKK bases in northern Iraq.

After a brief truce, fighting resumed in 2015, shattering hopes for a peaceful resolution to a conflict that has claimed more than 40,000 lives since 1984.