Nigeria was on Wednesday seeking to identify nearly 300 women and girls rescued from Boko Haram, raising hopes they may include schoolgirls seized in a high-profile kidnapping last year.
The army appeared to rule out any of the 200 girls being from the northeastern town of Chibok, who were snatched from their dormitories on April 14, prompting global outrage.
But Nigeria's defence spokesman urged caution, saying it was too early to tell and all those released from camps in the militants' Sambisa Forest stronghold were still being screened.
Chibok elders reacted angrily to the latest announcement, which comes after the military previously said some of the girls had been released, only to backtrack, and that it knew where they were.
"It is disheartening for our hopes to be dashed," said Enoch Mark, whose daughter and niece are among the 219 teenagers still being held by the Islamists.
"When we heard of the rescue we thought it was our girls. Parents kept contacting one another, hoping to get confirmation that their daughters were the ones rescued," he told AFP.
"However it's not surprising to me that our hopes have been dashed. This has happened several times. The government has lied a few times. To us, the government no longer has credibility."
Pogo Bitrus, whose four nieces are hostages, added: "We have never lost hope as a people but the issue is, if the military has the capacity (to rescue hostages) now, why didn't they do it before?"
Military at odds
Defence spokesman Chris Olukolade announced on Tuesday that troops rescued 200 girls and 93 women from the former colonial-era game reserve in northeastern Borno state.
He was initially cautious, saying it was "not yet confirmed" if the Chibok girls were among those released.
On Wednesday, he warned that it was "not safe or wise" to say the teenagers were not among the group. "You never can say. One or two could be among them."
But army spokesman Sani Usman was more categoric, stating: "From our preliminary investigations, the rescued girls are not those abducted from Chibok in April last year."
Details of the rescue came as Nigerian troops fought to flush out Boko Haram from its last remaining territory after a four-nation offensive against the group in the restive northeast.
The rebels, whose six-year insurgency to create a hardline Islamic state has left at least 15,000 people dead and some 1.5 million homeless, have lost control of towns in recent months.
At least 2,000 women and girls have been seized since the start of last year, Amnesty International said in a report earlier this month.
But the daring raid on Chibok -- and President Goodluck Jonathan's lacklustre response to the incident -- galvanised global demands for action, including international help in the rescue operation.
For Ayokunle Fagbemi, who heads the Center for Peacebuilding and Socio-Economic Resources Development, said Tuesday's rescue was a reminder that the overwhelming attention on the Chibok crisis has distracted from the plight of hundreds of other hostages.
"It is not only those Chibok girls alone in captivity," he told AFP.
Daniel Seun, a member of the Bring Back Our Girls group whose Twitter campaign helped bring the abduction to the world's attention, agreed that despite the disappointment, the reported rescue in Sambisa Forest should still be celebrated.
"We hope they are our girls, however we are happy if they got anybody," he said in Nigeria's capital Abuja.
The girls were initially said to have been taken to the Sambisa Forest, while others said they had been split up, with some sent to Cameroon and Chad or the Lake Chad region of northeast Nigeria.
Boko Haram leader Abubakar Shekau claimed the girls had been "married off" and converted to Islam. Nothing has been seen or heard from the 219 since a video appearance in May last year.
Both Bitrus and Mark said the latest rescue, while welcome, was part of the rollercoaster ride of emotions they have felt since the abduction.
"The chief of defence staff last year claimed to know where our girls were being kept but now we are being told a different story," said Mark, a church pastor.
"What has happened yesterday (Tuesday) has further opened an already festering wound. To us parents, its like the abduction happened yesterday.
"We were on the verge of celebrating the rescue of our daughters and now that mood has turned into mourning."