* Congo's army arrests Rwandan genocide suspect

* Extradition to genocide tribunal expected

* Rights group applauds arrest

(Adds comment from rights group, background)

By Joe Bavier

KINSHASA, Aug 12 (Reuters) - Authorities in Democratic Republic of Congo have arrested a man accused of planning the massacre of at least 2,000 Rwandan Tutsis during the 1994 genocide, a government official said on Wednesday.

Gregoire Ndahimana was arrested by Congolese soldiers on Sunday during U.N.-backed operations to stamp out Hutu rebel group, the Democratic Forces for the Liberation of Rwanda (FDLR), in the violence ravaged North Kivu eastern border province.

"He was discovered by our units operating in North Kivu ... He was hiding among the FDLR," Congolese Information Minister Lambert Mende said.

Ndahimana was a local administrator in the Rwandan town of Kivumu during Rwanda's genocide, in which around 800,000 Rwandan Tutsis and moderate Hutus were killed during 100 days in 1994.

According to his indictment by the International Criminal Tribunal for Rwanda (ICTR), he is responsible for the deaths of at least 2,000 Tutsis, most of whom were killed when Hutus bulldozed the church where they were being held.

ICTR prosecutors believe almost all of Kivumu's 6,000 Tutsi residents had been killed by July 1994.

The tribunal, based in the Tanzanian city of Arusha, was seeking Ndahimana's arrest for genocide or complicity in genocide, conspiracy to commit genocide, and crimes against humanity for extermination.

Twelve other ICTR indictees remain at large.

"(Ndahimana) is now in the hands of the military's operational authorities awaiting his transfer to Arusha," Mende said.

HUTU PRESENCE IN CONGO

Most of the former Rwandan military and Interahamwe militia members responsible for the genocide fled the country after Tutsi rebels, led by Rwanda's current president, Paul Kagame, swept through the central African nation, ending the killing.

Their presence in eastern Congo, Rwanda's giant western neighbour, served as a pretext for two Rwandan interventions, which sparked a 1998-2003 war and humanitarian catastrophe that has claimed 5.4 million lives over the past decade.

Relations between the former enemies have improved dramatically since late last year.

In December, Kinshasa allowed Rwandan soldiers to enter eastern Congo to take on the FDLR, whose ranks include some of the orchestrators of the genocide.

Earlier this year, the Congolese army, with the backing of the world's largest U.N. peacekeeping mission, launched operations against the rebels.

London-based rights watchdog Human Rights Watch (HRW) has condemned the operations' heavy toll on civilians, where hundreds of thousands of villagers have fled violence, but on Wednesday it applauded Ndahimana's arrest.

"The willingness of Congolese authorities to assist in the arrest and transfer of Ndahimana to the international tribunal in Arusha shows they are serious about improving relations with Rwanda and ending impunity for grave crimes," said Anneke Van Woudenberg, HRW's senior Congo researcher.

During her visit to Congo, U.S. Secretary of State Hillary Clinton on Tuesday called upon the Congolese government and the United Nations to better protect civilians in the east, who have been targeted for reprisal attacks by rebels. (Editing by Daniel Magnowski and Sophie Hares)

AlertNet news is provided by