The Democratic Republic of Congo's senate has stripped former President Joseph Kabila of his immunity, paving the way for his prosecution over his alleged backing of rebels in the east.

Authorities have accused him of treason and war crimes, saying there was a "substantial body of documents, testimony and material facts" linking Kabila to the M23 armed group, which has taken control of several towns in the mineral-rich east.

Kabila, 53, has not commented on the accusations but has in the past denied any connection with the insurgents.

Nearly 90 senators on Thursday voted in favour of his treason prosecution, while five opposed it.

"The senate authorises the prosecution and lifting of Joseph Kabila's immunity," declared senate Speaker Jean-Michel Sama Lukonde after Thursday's vote.

The former president, who led the country between 2001 and 2019, did not appear before the senate to defend himself.

After stepping down, he was given the title of "senator for life", which gives him legal immunity.

In order to pursue the charges against him, DR Congo's military prosecutor had asked the senate to lift this privilege.

Kabila has been living outside the country, in South Africa, for the past two years. But at the beginning of last month he said he would be returning to help find a solution to the conflict in the east.

A few weeks later, there were reports that the former president had come back and was in Goma, one of the cities captured by the M23.

But these were denied by his political party, the People's Party for Reconstruction and Democracy (PPRD).

Last month, the authorities banned the PPRD because of its "ambiguous attitude" to the occupation of Congolese territory by the M23.

Ordering the seizure of Kabila's assets, Justice Minister Mutamba said the former president should return to the country and "face justice... and present his defence".

Analysts say any trial of Kabila could further destabilise the country, which has been battling the M23 rebellion since 2012.

Kabila's party termed his prosecution "pure theatre" aimed at distracting Congolese people from the main challenges facing the country, AFP news agency reported.

Kabila, a former military officer, took over leadership of the country in 2001 at the age of just 29, after his father Laurent Kabila, was assassinated.

While Kabila supported Tshisekedi's rise to power, they later fell out and relations between their parties' coalition formally ended in December 2020.

Kabila has retained significant power through his political party and his influence within the ruling coalition, potentially undermining Tshisekedi's presidency.

Kabila left DR Congo in 2023, officially to study in South Africa.

Fighting between the M23 and the Congolese army and allied militia has continued in the east as the rebels attempt to expand their territory.

DR Congo and Rwanda, which denies accusations it backs the M23, may be edging towards a peace deal to end the fighting, which has seen hundreds of thousands of civilians forced from their homes in recent months.

The two countries signed a preliminary agreement in Washington last month and said they had agreed on a pathway to peace.

Last year, three M23 leaders were prosecuted in absentia by a military court and given death sentences for treason.

The government in March offered a reward of $5m (£4m) for help arresting the rebel leaders - Corneille Nangaa, Sultani Makenga and Bertrand Bisimwa.

Additional reporting by Wycliffe Muia in Nairobi