Niger says the bodies of 34 migrants, including 20 children, have been found in the Sahara Desert near the border with Algeria.
A government statement said they were found near the small desert town of Assamakka.
Interior Minister Bazoum Mohammed said it appeared they had died of thirst after being abandoned by their smuggler.
Niger lies on a major migrant route between sub-Saharan Africa and Europe.
Mr Mohammed said nine of the adults were women and five were men. He said members of the group had died between 6 and 12 June.
Two victims have been identified as Nigerian but the nationalities of the others are not yet clear.
The International Organisation for Migration (IOM) says about 120,000 people crossed through Niger's arid northern Agadez region last year.
Thousands of illegal migrants have travelled to Algeria in recent years, most of them via Mali and Niger. People smugglers have largely avoided Libya since it descended into political chaos.