Win Htein, a senior aide to Myanmar's ousted leader Aung San Suu Kyi, was sentenced to 20 years in prison on Friday on charges of high treason, media and one of his family members said.

Win Htein, 79, is a stalwart supporter of Suu Kyi (above) and a long time political prisoner during decades campaigning to end army rule.

He was arrested in the aftermath of a Feb 1 coup that...