Mursi, in his first public appearance since the army deposed him in July, rejected the proceedings and told the court on Monday: "I am Dr Mohammed Mursi, the president of the republic ... This court is illegal," a correspondent attending the trial reported.
Morsi, who was indignant and outraged as he attended the courtroom at a police academy in east Cairo, also demanded "coup" leaders be prosecuted, as thousands of his supporters rallied.
The Islamist leader slammed his overthrow by the army on July 3 after mass protests against his single year of turbulent rule.
"This was a military coup. The leaders of the coup should be tried. A coup is treason and a crime," he said.
Amid tight security, Morsi was flown in to the police academy by helicopter before arriving in the courtroom wearing a dark blue suit rather than the customary white detention clothes.
As he walked in, two of his co-defendants, senior Muslim Brotherhood leaders Essam al-Erian and Mohammed al-Beltagui chanted "Down with military rule" the hearing, and applauded Morsi.
Judge Ahmed Sabry Youssef banned cameras and recording equipment from the courtroom.
Morsi's supporters, battered by a bloody and sweeping police crackdown, accuse the army-installed government of fabricating the charges against the Islamist leader and on Monday rallied at several places in the capital against the military.
Outside, dozens of them brandished posters of Morsi and signs bearing anti-military messages. Thousands also protested in front of the constitutional court in the south of the capital.
Tensions were also high in front of the high court in downtown Cairo where pro- and anti-Morsi supporters had gathered.
Security forces completely closed Nahda Square -- site of a bloody crackdown on Morsi supporters in August -- and Cairo University, while military vehicles guarded police stations.
The authorities deployed 20,000 policemen for the trial, and warned they were ready to deal with any violence.
Morsi, who the army has held at a secret location since his ouster, is accused along with the other 14 of inciting the murder of protesters outside the presidential palace in December 2012.
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