Former Democratic Republic of Congo President Joseph Kabila has been sentenced to death in absentia for war crimes and treason.

The charges concern accusations that Kabila has been supporting the M23, a rebel group who have wreaked devastation across the country's eastern region.

Kabila was convicted on Friday by a military court of treason, crimes against humanity, and war crimes, including murder, sexual assault, torture and insurrection. He denied the charges, but did not appear in court to defend himself.

The ex-president rejected the case as "arbitrary" and said the courts were being used as an "instrument of oppression". His current whereabouts are unknown.

The 54-year-old led DR Congo for 18 years, after succeeding his father, Laurent, who was shot dead in 2001.

Kabila handed power to President Félix Tshisekedi in 2019, but they later fell out and Kabila went into self-imposed exile in 2023.

In April this year, the former president said he wanted to help find a solution to the deadly fighting in the east and arrived in the M23-held city of Goma the following month.

President Tshisekedi accused Kabila of being the brains behind the M23, and senators stripped him of his legal immunity, paving the way for his prosecution.

Decades of conflict had escalated earlier this year when the M23 seized control of large parts of the mineral-rich east, including Goma, the city of Bukavu and two airports.

Pointing to overwhelming evidence, the UN and several Western countries have accused neighbouring Rwanda of backing the M23 and sending thousands of its soldiers into DR Congo.

But Kigali denies the charges, saying it is acting to stop the conflict from spilling over onto its territory.

A ceasefire deal between the rebels and the government was agreed in July, but the bloodshed has continued.