The announcement came after the country’s military chief went on TV on Sunday to call for him to step down.
Mr Morales has endured weeks of anti-government protests since his election victory last month was called into question, with the Organization of American States later discovering “clear manipulation” at the polls.
Concerns were initially raised about a day-long gap in reporting results from the poll, just before a spike in votes for Mr Morales.
Mr Morales, who came to power in 2006, had promised a fresh election.
In his TV appeal, General Williams Kaliman said: “After analysing the situation of internal conflict, we ask the president to resign, allowing peace to be restored and stability to be maintained for the good of our Bolivia.”
He also urged Bolivians not to resort to violence.
