The UN's human rights chief has warned that Myanmar's treatment of minorities and suppression of free speech is setting back its political reforms.
Zeid Ra'ad al-Hussein said Myanmar (also known as Burma) was continuing to jail critics and quash peaceful protest despite promising to stop.
He warned politicians against fanning the "flames of prejudice" to win votes in the coming election.
A quasi-civilian government took power in 2011 after decades of military rule.
The UN rights chief said that the transition was seen by the world "as a story of promise and hope".
"But recent developments relating to the human rights of minorities, the freedom of expression and the right to peaceful protest are calling into question the direction of that reform and even threatening to set it back," he said.
He cited the persecution of Myanmar's Rohingyas, a Muslim minority group, and a case last week when 14 members of the Michuankan community were jailed for peacefully protesting against the alleged confiscation of their land by the military.
"Myanmar had promised to end the era of political prisoners, but now seems intent on creating a new generation by jailing people who seek to enjoy the democratic freedoms they have been promised."
He also raised concern over the recent violent clashes between the military and rebels in the north-eastern Kokang region, where more than 130 people have been killed.
Ties between Myanmar and UN rights officials have been tested in recent weeks.
Myanmar has accused Yanghee Lee, the UN's special rapporteur on Myanmar, of interfering in its internal affairs after she highlighted discrimination against Rohingyas.