The Nigerian military says it has rescued some of the schoolgirls who went missing during a Boko Haram attack on a village.
Officials and parents say 76 girls have been found, along with the bodies of two others.
The rescued girls were returned to the village of Dapchi on Wednesday.
Are any girls still missing?
Yes. At least 13 may still be unaccounted for.
The Reuters agency is quoting sources as saying 91 people remain unaccounted for after a roll-call at their school on Tuesday morning.
What is the official response?
Police and state officials say there is no evidence the girls have been abducted. The Yobe government later said in a statement the military had rescued some of the students from Boko Haram.
Nigerian authorities often deny or downplay such incidents, including the Chibok girls kidnapping and more recent abductions, as well as the scale of Boko Haram attacks in the north-east.
President Muhammadu Buhari has dispatched his foreign and defence ministers to Yobe to investigate the situation. Officials declined to confirm whether any of the students were missing.
How did the attack unfold?
Islamist insurgent group Boko Haram attacked Dapchi in the north-eastern state of Yobe on Monday evening.
Witnesses say they arrived in trucks, some mounted with heavy guns.
They went directly to the school, shooting sporadically.
Yobe state Police Commander Sumonu Abdulmaliki told reporters Boko Haram had also abducted three people from nearby Gaidam.
Chibok - the context
More than 20,000 people have been killed and two million forced to flee their homes in the northeast of Africa's most populous nation since Boko Haram began its insurgency in 2009.
Nigeria is still haunted by Boko Haram’s abduction of more than 270 schoolgirls from the town of Chibok in 2014.
The case drew global attention to the nine-year insurgency. It has sparked what the UN has called one of the world’s worst humanitarian crises.
270 girls were abducted from their school in Chibok in April 2014. Around 60 escaped soon afterwrds. Others have since been released after mediation. Around 100 are believed to be still in captivity.
Last month, Boko Haram released a video claiming to show some of the Chibok girls still in its custody. The group said they do not wish to return home.
Aid groups say Boko Haram have kidnapped thousands more adults and children. Many of their cases have been neglected.
What they are saying
"Everybody is celebrating their coming with songs and praises to God almighty. The only sad news is that two girls were dead and no explanation," - parent Barbara Umar.