At least 20, and possibly as many as 40, young mothers and three men have been kidnapped in Nigeria, in a siege likely perpetrated by Boko Haram. The victims were nabbed near Chibok, the same town which saw 300 schoolgirls kidnapped in April.

A member of a local vigilante group told Agence France-Presse that "available information revealed that the gunmen came around noon [on Saturday] and abducted 20 women and three young men left to keep watch on the village... all the males in the settlement were away in the bush with their herd (of cattle) for grazing when the abductors came to the village."

Another official, from the Miyetti Allah Cattle Breeders Association of Nigeria, said the kidnappers took 40 young women from the nomadic community. The official told AFP that kidnappings for ransom were not uncommon, saying "they come and go door-to-door bringing women outside and select young women and take them away in their vehicles and demand between 30 and 40 cows for their release." Usually, he said, the ransom is filled and the women returned, but authorities are not notified for fear that the militants will retaliate. 

This time, however, some authorities were aware of the incident. "We are working to establish the circumstances surrounding the abduction," said a government official, adding that only 20 women were taken. But Mike Omeri, in charge of the national information center, told CNN he did not know about the kidnapping.

Boko Haram has been stepping up violent attacks on civilians in recent months, and the government has been apparently unable to hold the militant group at bay.