He was arrested in August during operations against Rwandan rebels in North Kivu, eastern DR Congo.

His transfer is seen as a sign of improved DR Congo-Rwanda relations.

"We have done humanity a service, because the crime of genocide is an attack upon the peace and security of humankind," said DR Congo Justice Minister Luzolo Bambi Lessa, quoted by Reuters news agency.

Ndahimana was sent from Kinshasa to Arusha, Tanzania, where the International Criminal Tribunal for Rwanda (ICTR) is based.

 His wife and five children will be sent to Rwanda, reports the AFP news agency.  ICTR prosecutors believe that almost the entire 6,000-strong population of the town of Kivumu - where Ndahimana was mayor - was killed during the genocide.

After the 1994 killing spree, some of those responsible fled across the border to DR Congo, sparking years of unrest in the region, according to the BBC.

After years of mutual mistrust, DR Congo and Rwanda earlier this year started working together against both countries' rebel groups based along their common border.

Congolese Communication Minister Lambert Mende used the example of Ndahimana to renew calls that Rwanda to send Congolese rebel leader Laurent Nkunda to Kinshasa to face trial, AFP said.

Gen Nkunda was captured at the start of this year's joint operations and is believed to be under house arrest in Rwanda.