UN High Commissioner for Human Rights Louise Arbour said she is concerned that a series of recent trials of alleged terrorists in the aftermath of unrest in the city of Andijon might have convicted the wrong people.
Arbour said the trials "risked having produced unjust and unfounded convictions while the real perpetrators of atrocities remain unpunished."
In the past two months, Uzbek courts have convicted 151 people in closed-door proceedings.
Uzbek authorities say 187 people were killed in Andijon in May -- mostly militants, police, and soldiers. But international rights organization say troops fired indiscriminately and killed hundreds, mostly peaceful protesters.
Uzbek authorities confirmed on 23 December that Interior Minister Zakir Almatov handed in his resignation the previous day, citing "health reasons."
Almatov was replaced by Anvar Salihbaev.