The eight, who include former ministers and top military officials during and before the 1994 Rwandan genocide, were acquitted by the tribunal.

The UN and Niger signed a relocation agreement last November, but in late December Niger issued a seven-day expulsion order against them.

Niger said the decision was based on the Rwandan government's concerns about the men staying in Niger. The men had said they did not want to return to Rwanda.

Last month, former intelligence officer Innocent Sagahutu told the BBC that they were held in a safe house in the capital, Niamey, and that their documents were confiscated by Nigerien authorities.

The others who were in Niger are the former president's brother-in-law Protais Zigiranyirazo, former military intelligence Major François-Xavier Nzuwonemeye, plus former ministers André Ntagerura and Prosper Mugiraneza.

Former army officers Anatole Nsengiyumva, Alphonse Nteziryayo and Tharcisse Muvunyi complete the list.

The tribunal judge said that "what seemed to be a good solution" to problems of acquitted and released persons "has now turned into a possible human rights violation".