South African police said today they had arrested four people for the shooting of an exiled Rwandan army general on Saturday. Police spokesman Govind Samy would not give the nationality of those arrested, saying: "We are still busy with the investigation." But sources close to the investigation said that at least one of those arrested was a Rwanses national who served in the army with the victim.

Lieutenant-General Faustin Kayumba Nyamwasa was in hospital after being shot in the stomach in what his wife said was an assassination attempt.

Nyamwasa fled to South Africa this year after falling out with President Paul Kagame, later accusing him of using an anti-corruption campaign to frame opponents.

Rwanda's top diplomat has said in the past the country is pressing South Africa to extradite Nyamwasa for trying to destabilise Rwanda.

Foreign Minister Louise Mushikiwabo said there are very serious charges against Lt General Nyamwasa on a visit to London. She said that Nyamwasa is suspected of trying to destabilize Rwanda - while he was in the country, and also while he was in India, where he was serving recently as ambassador. The foreign minister said there is reliable evidence that Nyamwasa and another suspect were involved in illegal activities.

The Rwandan government has accused him of involvement in three February 19 grenade attacks in Rwanda's capital.

The attacks in central Kigali killed one person and injured 30. On Sunday, Rwanda's foreign minister dismissed suggestions yesterday that Rwanda was involved in the shooting in Joburg of Nyamwasa.

"It is ridiculous," Ms Mushikiwabo said. "We are not a government - and especially not President Kagame - that is inclined to assassinate its own citizens... This government has nothing to do with this kind of activity." Nyamwasa's wife Rosette was reported on Saturday as saying the attack was a politically motivated assassination bid as the gunman spoke Swahili.