A Rwandan military court jailed a brother of an exiled former army chief to nine years in prison for threatening state security, the defence ministry said in a statement Thursday.

On Wednesday, the military high court found Lieutenant-Colonel Rugigana Ngabo guilty and "sentenced him to nine years following accusations of threatening state security," the ministry said.

The court found him guilty of "rallying demobilised soldiers against the government, propagating rumours against the government, and inciting the population to subversive activities," the ministry said.

Both Rugigana Ngabo and the prosecution will appeal, the statement said.

Arrested in August 2010, Rugigana Ngabo is a brother of former Rwandan army chief Faustin Kayumba Nyamwasa, in exile in South Africa, and sentenced in absentia in early 2011 to 24 years in prison for threatening state security.

In June 2010 Kayumba Nyamwasa escaped an assassination attempt, which he said was orchested by the government of his former comrade-in-arms, Rwandan President Paul Kagame.

The Rwandan government has always ruled out any involvement.

The court hearing over the assassination attempt is currently ongoing in South Africa.