Zambia's President Edgar Lungu has denied claims of bankrolling a Rwandan rebel leader who is facing trial for attacks in his country in 2018 that left scores dead.

Rebel leader, Callixte Nsabimana, told a Rwandan high court on Monday that President Lungu promised his National Liberation Front (FLN) some $1m (£796,000) to help topple the the Rwandan government, AFP news agency reports.

He said President Lungu made a down payment of $150,000 in support of rebel attacks, the French agency reports.

But in a statement on Tuesday, President Lungu's spokesman said the "allegations are false and must be treated with the contempt they deserve".

"The peoples of Zambia and Rwanda continue to enjoy strong and fraternal relations founded on mutual respect," presidential spokesman Isaac Chipampe said.

Mr Nsabimana is facing 17 charges, Rwandan news website The New Times reports. They include formation of an illegal militia group, taking part in terrorist activities, killing, kidnapping and denying and undermining the 1994 genocide.

He has pleaded guilty to all charges, the website adds.