Parents of pupils who disappeared from their boarding school in Dapchi told the BBC their girls were still missing.
The state government has apologised for issuing a statement on Wednesday that said some had been saved by the army.

"We have now established that the information we relied on to make the statement was not credible," it said.
The Nigerian activist group, Bring Back Our Girls, has called on the government to release a list of the names in order to clarify how many pupils are missing.

The group was set up after the abduction almost four years ago of 276 girls from a school in Chibok, also in north-eastern Nigeria.
Parents originally said that around 100 children were thought to be missing following the attack in Yobe state.

Officials placed the figure far lower, at around 50, and initially said they had not been abducted. Instead, they were said to be hiding in the bush after fleeing the attack,
Then, in a statement released on Wednesday, the Yobe state government said they had been told by the army an unspecified number of girls had been rescued from the "terrorists who abducted them".

Reuters news agency quoted parents and a government official as saying two girls had died, 76 had been rescued and at least 13 were still missing.
But the state governor has backtracked on the statement and said the girls had not been found after all - leading five of the parents present at the briefing to faint with shock.

One parent, Kundiri Alhaji Bukar, told BBC Hausa: ''[The governor] said soldiers were dispatched but the military commander told him they could not locate the girls with the Boko Haram militants.
"He said no-one is really sure whether the girls were taken away by Boko Haram. But we on our part, we believe Boko Haram abducted the children."

Another parent, speaking anonymously, said people had been commending the authorities on their quick actions, but the change of position "angered the people".
"Many people broke into tears; some even collapsed," the parent said.

What has happened to the Chibok girls?

Last September, a group of more than 100 of the Chibok girls were reunited with their families at a party in Abuja.
Most of the group were released in May as part of a controversial prisoner swap deal with the Nigerian government that saw five Boko Haram commanders released.

But more than 100 schoolgirls are still being held by Boko Haram, and their whereabouts are unknown.
Boko Haram militants have been fighting a long insurgency in their quest for an Islamic state in northern Nigeria. The conflict is estimated to have killed tens of thousands of people.

The Chibok girls represent a fraction of the women captured by the militant group, which has kidnapped thousands during its eight-year insurgency in northern Nigeria