Egypt's ousted President Mohamed Mursi released a statement on Wednesday on his official Facebook page, a day after the army chief who toppled him was announced the country's new president.
Mursi urged Egyptians to continue their peaceful revolution, assuring them that they will see victory soon.
He assured them that they are backed by a majority and described last week's presidential elections as a "charade".
Former army chief Abdel Fattah al-Sisi, who led the army last year as it ousted Mursi, easily won a recent vote and will be sworn into office as the country's president on Sunday.
In Wednesday's statement, Mursi described Sisi as the "leader of the coup" and asked Egyptians to unite against him.
"God knows I did not spare any efforts to confront corruption and crime through law once and many times through revolutionary procedures," Mursi said in his letter, promising to continue to confront those things.
Mursi directed a special word to Egypt's youths, "You are today and tomorrow ... The present and the future."
The ousted president said that free countries do not acknowledge the "criminal coup regime" because Egyptians continue to revolt against it peacefully.
Mursi who is in prison pending several allegations was ousted last July in response to mass demonstrations against his rule.
The official page has not released any statements or posts since July 3 last year, the day the Islamist president was overthrown.
The page has more than 3.5 million followers.