CAIRO (Reuters/AFP) - Deposed Islamist Egyptian president Mohamed Mursi said on Wednesday he was kidnapped and held by the Republican Guard and then at a naval base a day before he was formally ousted by the military.

He also intends to sue the army-installed authorities over his ouster in July, his lawyer told reporters on Wednesday.

Few details had emerged on Mursi's whereabouts since army chief Abdel Fattah al-Sisi ousted him on July 3 and announced plans for elections.

Lawyer Mohamed Damati read on television what he said was a letter from Mursi to the Egyptian people. For the first time, Mursi indicated that he was held against his will as early as July 2, a day before the army announced his removal following mass protests against his rule.

He is currently in prison as he faces trial over his involvement in the death of protesters outside his presidential palace in 2012.