Kenyan activist Boniface Mwangi and Ugandan activist Agather Atuhaire alleged on Monday that Tanzanian security officers sexually assaulted them while they were detained in Tanzania last month.
Spokespeople for Tanzanian authorities did not immediately respond to requests for comment on these allegations.
Mwangi and Atuhaire were detained in Dar es Salaam after arriving to attend the court appearance of Tanzanian opposition leader Tundu Lissu, who faces treason charges.
Tanzanian authorities have not commented on their detentions, but President Samia Suluhu Hassan had warned foreign activists against interference.
Mwangi recounted being blindfolded, stripped, questioned about his devices, and sexually assaulted by interrogators who also photographed him.
Atuhaire similarly reported being blindfolded, tied up, and sexually assaulted.
Both activists were eventually left near their respective borders.
Lissu was arrested in April and charged with treason over a speech.
His case highlights a growing crackdown on opponents of President Hassan, who has faced criticism for arrests and abductions despite initially easing political repression.
Hassan has stated her government respects human rights and ordered an investigation into past abductions.
