KAMPALA, Jan 19, 2025 (BSS/AFP) - Ugandan former presidential candidate Kizza Besigye, who is on trial on charges including treason, has been placed in solitary confinement, a leading official in his party told AFP Saturday.

"Besigye at the moment is in a prison within a prison," said Doreen Nyanjura, deputy mayor of Kampala and a leading figure in the Forum for Democratic Change (FDC).

"He is not allowed to interact with the rest of the prisoners and not allowed to go for prayers," she added. "He is alone in a cell."

Nyanjura was speaking after returning with other party officials from the Luzira maximum security prison on the shores of Lake Victoria near the capital Kampala.

Besigye was only allowed to speak to visitors -- including members of his family -- via telephone, she said.

Prison officials had also refused to let supporters supply him with food from outside the jail, to supplement what she said were the inadequate meals offered inside.

Uganda's President Yoweri Museveni, she said, was "determined to kill" Besigye.

Prison spokesman Frank Baine told AFP that his treatment was strictly in accordance with his human rights. "The claim of Besigye being mistreated is all lies," he added.

Besigye is a former comrade-in-arms and personal physician to Museveni, but became a government target after he joined the opposition 25 years ago.

His wife, Winnie Byanyima, claims he was kidnapped while on a trip to Kenya in November and is now being prosecuted on charges that include treason, which is punishable by death.

When the trial resumed earlier this month, one of Besigye's lawyers was sent to prison for nine months.

Byanyima, who is the executive director of UNAIDS, this week denounced the court martial as a "sham".

The UN and several rights organisations have voiced their concern about the suppression of the opposition in Uganda, in the run-up to the 2026 presidential elections.