KAMPALA: Ugandan authorities have detained top Rwandan genocide suspect Idelphonse Nizeyimana, the so-called Butcher of Butare, officials said Tuesday.

The United States had offered a five million dollar reward for the capture of Nizeyimana, a former Rwandan army intelligence officer and one of the four most wanted suspects on an International Criminal Tribunal for Rwanda (ICTR) list.

Nizeyimana, who was captured Monday in a Kampala hotel, served as an intelligence officer in the southern university town of Butare at the time of the mass killings in which an estimated 800,000 people died in 100 days in 1994.

He is wanted for genocide, complicity to commit genocide and direct and public incitement to commit genocide.

Nizeyimana, a Hutu, is accused of being one of the two leading planners of massacres in Butare, notably of ethnic Tutsi students and lecturers at the university and of ordering the execution of Queen Rosalie Gicanda, the widow of King Mutara III and a figure revered by Tutsis.

Massacres began later in Butare than in other parts of Rwanda. Hutus and Tutsis had lived there in harmony there and it was only after the removal and execution of the local prefect that the killings started.

Nizeyimana was handed over to authorities of the Tanzania-based ICTR.

"We got him. He was in a hotel and our intelligence located him. Through Interpol the police was able to identify him (and check) that he was the one on the wanted list," Ugandan police spokeswoman Judith Nabakooba told AFP.

The other top fugitives on the ICTR list are Felicien Kabuga, the suspected genocide financier, former defence minister Augustin Bizimana and Protais Mpiranya who commanded the presidential guard.

Nizeyimana is also on a United States list of Rwandan genocide suspects with a five million-dollar (3.5 million-euro) bounty on his head.

Rwandan prosecution spokesman Augustin Nkusi welcomed Nzeyimana's capture but said Rwandan authorities would prefer that he be extradited to face trial at the scene of his crimes.

Nizeyimana was captured after a tip-off and did not resist arrest, the deputy chief of Uganda Interpol, Elly Womanya, said.

His arrest was a collaborative work between the ICTR, Interpol and Ugandan authorities.

"He is in the custody of the ICTR," Roland Amoussouga, a spokesman for the tribunal told AFP in Arusha, Tanzania.

Police said Nizeyimana arrived in Uganda around October 1 from neighbouring Democratic Republic of Congo (DRC) and may have been heading for Nairobi or Tanzania.

Since the recent thaw in Rwanda-DR Congo relations, Kinshasa has been under pressure to hand over to the ICTR suspected organisers of the genocide hiding there.