People watch on while a speech by Turkey's President Recep Tayyip Erdogan is shown on a big screen in Taksim Square on July 20, 2016 in Istanbul, Turkey. Turkey's president Recep Tayyip Erdogan has announced tonight a three month state of emergency following Friday night's failed coup. Clean up operations are continuing in the aftermath with the death toll now standing at 246 and 1,536 wounded. [Photo/VCG]

Before announcing the state of emergency, Erdogan said the sweep was not yet over and that he believed foreign countries might have been involved in the attempt to overthrow him.

Speaking through an interpreter in an interview with broadcaster Al Jazeera, Erdogan dismissed suggestions that he was becoming authoritarian and that Turkish democracy was under threat.

"We will remain within a democratic parliamentary system. We will never step away from it," he said.

Academics were banned from traveling abroad on Wednesday in what a Turkish official said was a temporary measure to prevent the risk of alleged coup plotters at universities from fleeing. TRT state television said 95 academics had been removed from their posts at Istanbul University alone.

Erdogan blames a network of followers of an exiled US-based cleric, Fethullah Gulen, for Friday night's attempted coup, in which more than 230 people were killed and hundreds more wounded as soldiers commandeered fighter jets, military helicopters and tanks in a failed effort to overthrow the government.

Erdogan, an Islamist who has led Turkey as prime minister or president since 2003, has vowed to clean the "virus" responsible for the plot from all state institutions.