"We demand the immediate release, without condition, of all those arrested and detained by security services in the two states," Floribert Chebeya Bahizire, the president of the human rights NGO, La Voix des sans voix (Voice of the voiceless), said at a news conference in Brazzaville, capital of the Republic of Congo.
He spoke after a meeting attended by human rights groups from the two countries.
According to the NGOs, the two countries have security agreements that allow their security services to operate in each other's territories to track down political dissidents, asylum seekers, refugees and people with views divergent from those of their respective governments. They claimed that those arrangements provided for arbitrary arrest, illegal detention, extradition and forced disappearance.
Bahizire called on the two states to respect regional and international human rights conventions to which they were signatories.
A communiqué issued by the groups identified DRC citizens Major Germain Ndabamenya Atikilome, Major Médard Mabwaka and Cpt Bosch Ndala Umba as some of the people held since 2004 by the directorate of military intelligence.
In the Republic of Congo, Lt Col Serge André Mpassi, Cpt Bartel Bibondo, Cpt Bertin Pandi Ngouari, Lt Louis Marie Mizingou and warrant officer Alphonse Miyalou were arrested and detained at the central prison in Brazzaville between January and March 2005 for allegedly breaching state security, according to the communiqué.
The NGOs also launched an appeal for establishing a special tribunal to investigate the so-called 'beach disappearances' of 1999 in the Republic of Congo, as well as the setting-up of an international tribunal for the DRC to look into all international crimes that did not fall under the International Criminal Court.
At least 353 returning refugees were allegedly killed in 1999 as they returned from DRC where they had fled in 1998 to escape civil war in the Republic of Congo.