During a swearing-in ceremony for new officers in August, the five held their swords to the sky, saying: "We are the soldiers of Mustafa Kemal" and vowed to defend "the secular democratic republic".

They were referring to Mustafa Kemal Ataturk, who founded modern Turkey in 1923 after the disintegration of the Ottoman Empire at the end of World War I.

Ataturk pushed through many reforms and made Turkey a strictly secular state -- a move which Erdogan and his Islamist-rooted AKP party have pushed back against since coming to power in 2002.

Images of the troops taking the pledge in front of Erdogan sparked fierce debate in Turkey.

Long seen as the guardian of Ataturk's principles, the military staged coups in 1960, 1971 and 1980 and forced Erodgan's Islamist mentor, Necmettin Erbakan, to resign as premier in 1997.

Following another failed putsch in 2016, the government carried out vast purges, removing those perceived as hostile to Erdogan from the military ranks.

Shortly after the swearing-in ceremony, Erdogan vowed to ensure those involved "receive the punishment they deserve".

"We will not let our army to be used to settle political scores," he said.

On Friday, the defence ministry said all five trainee officers and three of their superiors had been dismissed from the military.