Tanzanian police detained two senior opposition figures on Thursday, their party said, as they drove to a court hearing for party leader Tundu Lissu, who has been charged with treason.

Police detained CHADEMA party Deputy Chairperson John Heche and Secretary General John Mnyika as they headed to Kisutu Magistrate Court in Dar es Salaam, party spokesperson Brenda Rupia said.

The reason for their detention was not immediately clear. A police spokesperson did not immediately respond to a Reuters request for comment.

Lissu, the runner-up in a presidential election in 2020, was charged with treason this month over what prosecutors said was a speech calling on the public to rebel and disrupt the October election. He was not allowed to enter a plea on the treason charge.

The charges against Lissu have placed President Samia Suluhu Hassan's human rights record under the spotlight as she seeks for re-election. Hassan has said the government is committed to respecting human rights.