At least 1,113 people have died in regime custody since the February 2021 coup, according to the Assistance Association for Political Prisoners (AAPP).
Many were shot, set on fire or tortured to death shortly after being detained, according to the rights group.
Resistance fighters, supporters of the National League for Democracy (NLD), democracy activists, religious leaders, striking civil servants and refugees are among those in custody.
Four political prisoners, including former NLD lawmaker Ko Phyo Zeya Thaw and veteran democracy activist Ko Jimmy, were executed by the junta in July last year for fighting the regime.
During 2023, more than 110 people died in junta detention in Sagaing, Magwe, Mandalay, Bago, Yangon, Ayeyarwady and Tanintharyi regions and Mon, Kayah and Chin states, according to the AAPP.
U Nyo Tin, 65, was tortured to death after being detained by the junta forces and pro-junta Pyu Saw Htee militia members on March 23 in Mya Kan village, Khin-U Township, Sagaing Region. Troops also set his village on fire. U Nyo Tin was discovered at his house after junta forces left.
On March 18 junta forces raided Say Min Taw village on the Htilin- Gangaw road in Htilin Township, Magwe Region, and killed two residents, including mentally unstable Than Min Aung, the AAPP reported.
On March 16 Kar Kyaw, 70, and Than Htwe, who was mentally ill, were killed in detention.
The AAPP said most deaths in junta custody occurred in Sagaing Region, followed by Mandalay and Magwe regions. It said the real figures will probably be much higher.
Deaths in junta detention
1,103 detainees were killed in junta detention
Victims by gender
Victims by age group
Special conditions of death in junta custody
Victims by region and state