The abduction of foreign tourists in the Bwindi National Park in Uganda is being blamed on Rwandan rebels known as the Interahamwe.

The Interahamwe are viewed by the Rwandan authorities as the remaining hardcore of the force which carried out much of the mass killing during the genocide of 1994.

A Tutsi-led army ended the massacres by seizing power and driving the Hutu extremists out of Rwanda.

Close to five years on, the Interahamwe militias are still fighting their own war, sometimes inside Rwanda, but now more often just across the border.

Cross-border war

The Rwandan Government says a large-scale military campaign has cleaned up the troubled northwest of Rwanda, but accepts that the rebel units have since regrouped in the neighbouring Democratic Republic of Congo.

The Interahamwe's exact strength is not known, and it has proved difficult to identify a clear political and military leadership.

But there have been reports that thousands of Rwandan rebels have been brought under arms by Congo President Laurent Kabila to support his fight against Congolese rebels backed by Rwanda and Uganda.

Mountain strongholds

A report last year by the United Nations confirmed that the Interahamwe were still receiving arms and money from outside supporters.

The militia's main strongholds are thought to be in the mountains which straddle the borders of Uganda, Rwanda and the Democratic Republic of Congo.

It is a region of volcanoes and thick forests, which is also home to hundreds of mountain gorillas.

But wildlife tourism, once a lucrative source of revenue, has been severely hit by the continuing conflicts in this part of Africa, and the Interahamwe have made a point of targeting gorilla sites.