After being held captive for three years, 82 Nigerian girls abducted from their boarding school in 2014 have been freed.
The young women have been flown into the capital Abuja and have met with President Muhammadu Buhari.
He expressed his joy in a government statement, saying, "I cannot express in a few words how happy I am to welcome our dear girls back to freedom."
Before meeting President Muhammadu, the girls were driven through the city in a military convoy to a hospital, where they underwent medical examinations.
There, they were welcomed by his chief of staff, Abba Kyari.
"Welcome, our girls. Welcome, our sisters. We're happy to have you back. We are very glad that you are back. And every Nigerian today must be forgetting every other hardship and suffering, because this is a very joyous moment. Welcome, welcome, welcome."
Officials in Nigeria say the girls were handed over in exchange for five Boko Haram prisoners.
After months of negotiations, the release was secured with mediation by the International Committee of the Red Cross.
International Red Cross spokeswoman Aleksandra Mosimann says the girls will be reunited with their families soon.
"The International Committee of the Red Cross, over the last two days, completed an operation which resulted in the transfer of 82 Chibok girls back to the government. The operation took us two days because of the bad weather and some hiccups along the way, but we are very happy that 82 girls will be reunited with their families very soon."
In the remote north-eastern town of Chibok, families have been waiting anxiously to find out whether their daughters were among those released.
In the capital, some parents have joined around 70 members of the Bring Back Our Girls group, who are rejoicing at the news.
But they, too, are unaware if their daughters have been freed.
Enoch Mark, the father of two missing girls, is one of those.
"Three years is not a joke. If it happens they are not back, what I can do? And even if my daughter is not among (them), I'm not the only person. The parents of the other daughters that are absent, we will still join together and pray to God, hoping that, sooner or later, they will be back."
The release is the largest release since Boko Haram seized 276 schoolgirls from Chibok three years ago.
But over 113 remain unaccounted for.
Girls who escaped have said previously that some of the others died in captivity and others had decided to join the side of Boko Haram.
Aisha Yesefu, co-convener of the Bring Back Our Girls group, which has long been campaigning for the girls' return, says the group is celebrating the latest news.
But she says the group will continue the fight until all of the girls are free.
"I mean, right now, I'm speechless. It means everything to our group, not just to our group but to our Chibok parents and Nigerians as a whole and the world as a whole. It means that we can go after and get our girls back. And so we have 82 today. It's such heartwarming news that we have been able to get 82 more of our girls brought back home. And so, right now, we have 106 that have been brought back home. We have 113 still waiting for us to go out there and get them and bring them back home."
Boko Haram has waged an eight-year fight to create a caliphate, killing thousands and forcing more than 2 million from their homes.
The abduction of the Chibok girls caught global attention when the hashtag #BringBackOurGirls went rampant on social media.
But Ms Mosimann, from the International Red Cross, says thousands more children have been kidnapped in the conflict.
"Apart from the Chibok group, there are so many other children in there, thousands who are not with their families today, because of the armed conflict that's raging in the north-east of Nigeria. They also need to be reunited with their families, and I hope that many more families are going to get the good news that the families of the 82 girls are getting today."
