An official working for Aung San Suu Kyi's government was sentenced to six months in jail by a Yangon court Friday for criticising Myanmar's army chief in a Facebook post.
It is the latest verdict to highlight lingering limits on free speech in the young democracy, where the military remains a powerful player despite the end of junta rule.
Myo Yan Naung Thein, a researcher for Suu Kyi's ruling party, was arrested in October for urging the head of the army to resign over deadly raids on police posts in the north of Rakhine State.
The attacks, by a militant group claiming to represent Myanmar's stateless Rohingya Muslims, sparked an army crackdown so brutal UN investigators believe it may amount to crimes against humanity.
In a Facebook post just days after the October raids, Myo Yan Naung Thein said Senior General Min Aung Hlaing was "shameless" for allowing the raids to happen and called for his resignation.
The 43-year-old appeared calm as he heard the verdict read out in Yangon's Kamayut township court on Friday, flanked by military officers.
But he struck a defiant note as he left the court, criticising the army's continued grip on power even after Suu Kyi's National League for Democracy (NLD) won the first free elections in half a century in 2015.
Under a junta-era constitution the military still controls a quarter of parliament seats and the ministries of home affairs, defence and borders.
"It's obvious that we have two groups ruling Myanmar, not only our (elected) government," he told journalists.
Myo Yan Naung Thein has been held in jail since his arrest and will be able to walk free in a few weeks because of time served.
Prosecutions under a controversial online defamation law have soared since the NLD took power in March 2016, targeting both those who have criticised the army and the new civilian administration.
The law was originally passed by the previous military-backed government as part of a raft of measures designed to attract foreign investment in Myanmar's telecoms sector.
But activists say it is increasingly being used to stifle free speech and criticism of the government, dashing hopes the NLD would usher in a new era of openness after half a century of repressive military rule.
At least 46 cases have been brought over the past year, compared to just seven between when the legislation was passed in 2013 to when the NLD took power.
They include cases against two officials from one of the country's biggest media groups, a man who called the president 'crazy' on Facebook and another who wrote curses about the army on his car.
Last month a mother launched proceedings against her own son for writing insulting comments about her relationships on Facebook.