The wives of two prominent officials have been arrested in Niger following the dismantling of an alleged baby-trafficking ring this week, according to a police source.
More than 20 suspects were arrested on Monday as part of an international investigation involving police from Nigeria, Benin and Niger, the source told the AFP news agency.
Those arrested were "mostly women" and included one of the wives of Niger's former prime minister and current parliament speaker Hama Amadou, who is seen as the main challenger to President Mahamadou Issoufou in elections due in 2016.
The wife of Abdou Labo, the agriculture minister, was also detained.
The babies trafficked are thought to have arrived in Niger from Nigeria via Benin.
"The trafficking network is used primarily by couples who are unable to have children," a source close to the case told AFP.
A number of civil servants and health workers were also detained. Some suspects were referred to the public prosecutor on Wednesday, the police source said.
"Baby factories" - private clinics where young girls sell their newborns to couples who are unable to conceive - are regularly dismantled in Nigeria.
Cases in which mothers give up babies born from rape have been reported at such clinics, but young women facing unwanted pregnancies are more common, according to the Nigerien authorities.
The newborns are sold for several thousand dollars, with boys fetching more than girls. The mothers receive around $200.
Human trafficking is the third most common crime in Nigeria, behind fraud and drug trafficking, according to the UN.