The international community must pressure Tanzania to investigate police officers accused of sexually torturing Kenyan and Ugandan activists last month, a rights coalition in Kenya said on Tuesday.

Boniface Mwangi and Agather Atuhaire were detained in Tanzania's business capital Dar es Salaam between May 19 and 23 when they attempted to attend the trial of opposition leader Tundu Lissu, who is charged with treason and faces a potential death penalty.

They have both detailed torture and sexual abuse by the police officers who detained them.

On Tuesday, the Police Reforms Working Group, a coalition of Kenyan rights organisations, called on "the East African Community and the international community to demand that the government of Tanzania hold accountable the police officers and their commanding officers responsible for the torture, assault, and sexual assault committed against Boniface Mwangi and Agather Atuhaire."

'Brutal campaign against' dissent

The group spoke alongside the Law Society of Kenya (LSK) at a press conference in Nairobi.

"Torture and cruel, inhuman and degrading treatment are serious crimes under multiple treaties and international law," they said.

"The government of Tanzania must arrest and prosecute all officers suspected of responsibility for the human rights violations against Boniface Mwangi and Agather Atuhaire and bring them to justice in a fair trial."

Irungu Houghton, director of Amnesty International Kenya, said Tanzania was engaged in "a brutal campaign against all forms of dissent" ahead of elections in October.

President Suluhu seeks election

President Samia Suluhu Hassan is running for election but her government has banned the main opposition party, Chadema, after it insisted on reforms before taking part.

The Tanzanian government has not responded to several requests for a response to the accusations by Mwangi and Atuhaire.