Turkey's president has attacked military graduates who took the prosecular oath during a graduation ceremony, vowing that those behind it will be "cleansed" from the army.

Recep Tayyip Erdogan described those involved as "opportunists".

He added that the investigation is ongoing and promised that "several insolent persons responsible will be purged from the army." "Whoever they are, it is not possible for them to be part of our army," he warned.

On August 30, Erdogan attended the graduation ceremony at the Turkish Military Academy in Ankara. Ebru Eroglu led the class of 960 graduates in reciting the official military oath to defend Turkey, the Associated Press reports.

However, footage captured about an hour later showed around 400 graduates gathered in a field raising their swords and chanting "We are the soldiers of Mustafa Kemal", referring to the secular founder of modern Turkey, Mustafa Kemal Atatürk.

Kara Harp Okulu röm bincırisi Teğmen Ebru Eroğlu 'nun şarlarından, asaletinden ve ettirdiği yeminden pkklı ya da fetöcü bir hain değilisseniz ve açır gurur duyar benim gibi izlerken gözyaşlarınız tutamaziz. Biz Atatürkçü ordudan sazdızız.
How happy is the one who says I am a Turk pic.twitter.com/5dsi3LuzaS

— Tuğba Arslan (@taslan82) September 2, 2024

Eroglu then led the group in the Officers' Oath, in which they pledged to defend a "secular, democratic Turkey". That Academy oath was abolished in 2022. Turkey has become more openly religious under Erdogan, rejecting some of the secularist traditions of the original Kemalist republic.

The Turkish military has traditionally seen itself as the guarantor of secularism, which has resulted in a series of coups.

The military led three coups between 1960 and 1980, and in 1997 overthrew the conservative government. However, an attempt to oust Erdogan in 2016 was thwarted and thousands of people were removed from the armed forces, judiciary and other public institutions.

Erdogan ally Devlet Bahceli, leader of the Nationalist Movement Party, was among the first to call for an investigation into the disputed oath. On Thursday, the Ministry of Defense confirmed that an investigation had been launched.