Media in Myanmar say Aung San Suu Kyi has been charged with breaking the country's official secrets law. It was the fifth charge filed against her since she was detained during the February 1 coup.
Media reports on Thursday quoted her lawyer.
The other four charges include illegally importing handheld radios and using them without permission.
Analysts say the military is seeking to underscore its legitimacy and block Aung San Suu Kyi from returning to politics.
Anti-coup protesters continued their rallies on Thursday. A local human rights group said security forces gunned down five people.
The group claimed the death toll in protests since the coup has risen to at least 543.