Five hostages kidnapped in Niger last month were freed Saturday and the other captive was killed, according to an NGO of the land-locked African country.

"The six humanitarian workers kidnapped in Niger in October, including five Nigeriens, were freed Saturday and the Chadian, Aime Soulembaye, injured in captivity, succumbed to his injuries," Sani Sayadi, an official of the BEFEN (Well-being of the Nigerien Women and Children), told Xinhua.

The BEFEN provides humanitarian aid to 2,000 or so women and children suffering from malnutrition and severe diseases. The six worked with the organization before kidnapped on a mission in central Niger.

The official did not identify the kidnappers, nor elaborate on conditions of detention or how the hostages were freed.

"We are ignorant of all these. One of the ex-hostages called us to announce their release and the death of our colleague Aime," he said. "The violent killing of our colleague ... is a unjustifiable tragedy and incomprehensible for the whole of human world," he added.

The BEFEN official also disclosed that the ex-hostages were transported to Niamey by Nigerien defense and security forces.

Aime and the other five humanitarian workers were kidnapped on the night of Oct. 14 by armed men in the region of Dakoro, which is in the neighborhood of Tahoua bordering northern Mali in the west.

Rebels linked to the Al-Qaida branch in North Africa (AQIM) have taken the northern part of Mali since April in the aftermath of the March 22 military coup.

AQIM has threatened to kill four French hostages taken in Niger two years ago if France supports a military intervention being planned by the West African bloc ECOWAS.