The Niger government declared three days of mourning, CNN reported, citing state news agencies. The newspaper Le Sahel said the Niger government "presented its condolences to the victims' families."
Azaoua Mahaman of the group Synergie told CNN Thursday the group was trying to leave Niger, one of the world's poorest countries, hoping for economic opportunity in Algeria. Their vehicles broke down in the Sahara desert in northern Niger.
Laura Lungarotti, a migration specialist with Synergie, said northern Niger has become a major transit route for people from that country and its neighbors hoping to reach Algeria, Libya or Europe. She said some get turned back at the border with some taken to refugee camps while others are left on their own.
Mahaman said the people found this week were mostly women and children and had been dead for some time.