The Nigerian army has relocated 275 women and children recently rescued from the militant Islamist group Boko Haram, officials say.
They said they were taken from a camp in the north-eastern city of Yola and flown to an unknown destination.
Camp officials said there were suspicions some of the women had been communicating with militants.
Nigeria’s military, which has not yet commented, has put increasing pressure on Boko Haram in recent months.
Backed by soldiers from Chad, Cameroon and Niger, the Nigerian army has managed to liberate a number of towns from the militants since they launched a military operation in February.
However, sporadic attacks and violence have continued, with thousands killed in the last year alone.
‘Serious humanitarian crisis’
The group of women and children were brought to Malkohi camp in Yola on 2 May, after their rescue from a Boko Haram camp in the Sambisa Forest.
At the time, the women said some members of their group were killed when the militants pelted stones at them because they refused to run away as the army approached.
A spokesman for the government body managing the camp, Sani Datti, told the AP news agency that he was aware soldiers had removed the group. But said he had no more details of what he described as an “entirely military affair”.
Separately on Thursday, the International Committee of the Red Cross (ICRC) said the Boko Haram insurgency had caused “one of the most serious humanitarian crises in Africa”.
General view of school in Yola, Nigeria, where victims are recovering (May 2015)
Recent captives were rescued from what is thought to be the group’s last Nigeria stronghold
“Whole communities have fled their villages and endured unimaginable suffering… even if the fighting stopped tomorrow, it will take years of investment and painstaking work to rebuild livelihoods and services,” ICRC president Peter Maurer said.
He has just returned from a trip to the two north-eastern cities of Maiduguri and Yola, where thousands of people have fled the violence.
He said the charity was seeking an additional $65 million (£41m; €58m) to support its operations in Nigeria as well as in Chad, Cameroon and Niger, where the fighting has spread.
Further support was also needed for the victims of sexual violence, he said, amid widespread evidence the militants raped some of the kidnapped women and girls.
About 1.5 million people have been displaced and hundreds more abducted since the group launched their violent uprising in 2009. More than 15,500 people have been killed in the fighting.
The group is still holding many women, girls and children captives including 219 schools girls it kidnapped from a school in Chibok in April last year.
The name Boko Haram, loosely translated from the region’s Hausa language, means “Western education is forbidden”.BBC