The International Criminal Tribunal for Rwanda (ICTR) chief prosecutor, Hassan Jallow, has called for scaled-up efforts to apprehend perpetrators of the 1994 genocide against the Tutsi still hiding from justice.

Speaking during the 20th commemoration event in Arusha on Thursday, Jallow also asked countries holding suspects to prosecute or transfer them to Rwanda to face justice.

"Several suspected genocidaires whom the ICTR has not been able to prosecute due to the limitation of its mandate must in accordance with the requirements of international law, be prosecuted by the host countries or extradited to Rwanda to stand trial,” he said.

He added that there was no basis for anyone to dispute the fact that there was a campaign to exterminate the Tutsi in Rwanda in 1994.

"The fact of the Genocide against the Tutsi is part of world history; a fact as certain as any other; a classic instance of a fact of common knowledge,” Jallow told mourners gathered at ICTR’s Simba Hall.

He said as the tribunal moves closer to its end in 2015, much remains to be done to apprehend fugitives like Félicien Kabuga, Protais Mpiranya (former commander of the presidential guard) and Augustin Bizimana, the former minister of defence—accused of a key role in the killings that claimed over a million lives.

The ceremony was also attended by justice minister Johnstone Busingye, IBUKA president Jean Pierre Disingizemungu, and Yvonne Kabanyana, the head of AVEGA, an association of Genocide survivors.

Bongani Majola, the registrar of the tribunal, acknowledged that the creation and work of ICTR can never justify the failure of the international community to prevent the Genocide.

On Friday, the East African Community (EAC) Secretariat and the Rwandan High Commission in Tanzania held an hour-long walk to remember in Arusha Town.   

Former Tanzanian President Benjamin Mkapa, Rwanda’s High Commissioner to Tanzania Ben Rugangazi, and EAC Secretary General Dr. Richard Sezibera participated in the walk.