Nairobi/Kigali  - Congolese rebel leader Laurent Nkunda has been arrested in Rwanda after attempting to stand against a joint Rwandan-Congolese military operation in the Democratic Republic of Congo, the operation's commanders said Friday.

Almost 4,000 Rwandan troops on Tuesday entered DR Congo under an agreement with the Congolese government to hunt down Hutu rebel forces formed after the 1994 massacre in Rwanda.

Nkunda's Tutsi rebel group, the National Congress for the Defence of the People (CNDP), which was allegedly backed by Rwanda, is also opposed to the Hutu militia.

"Ex-general Laurent Nkunda was arrested on Thursday ... while he was fleeing on Rwandan territory after he had resisted our troops at Bunagana with three battalions," the joint operation said in a statement.

The CNDP in October launched a major offensive that sent more than 250,000 people fleeing.

A recent split in the CNDP appeared to have weakened Nkunda's position.

The Congolese government has promised to tackle the Hutu militia on several occasions but has failed to do so. The CNDP said this failure was one of the main reasons it was forced to take up arms again.

Many of the Hutu fighters fled over the border from Rwanda in 1994 after taking part in the slaughter of an estimated 800,000 Tutsis and moderate Hutus.

The Hutu groups were also involved in the 1998-2003 war in DR Congo, which has led to the deaths of more than 5 million people and displaced more than 1 million. (dpa)