The 82 schoolgirls released by Boko Haram Islamist militants are to meet Nigerian President Muhammadu Buhari.
They were escorted to the reception in the capital Abuja by armed soldiers, after a check-up at a medical centre.
The girls were handed over on Saturday in exchange for Boko Haram suspects after negotiations.
They were from a group of 276 abducted in north-eastern Nigeria in 2014. Before the latest release, about 195 of the girls were still missing.
The number of Boko Haram suspects released by authorities remains undisclosed.
In Abuja, President Buhari’s chief of staff Abba Kyari said: “Welcome our girls. Welcome our sisters. We’re happy to have you back.
“We’re very glad that you are back. That every Nigerian today must be forgetting every other hardship they’re suffering, because it is a very joyous moment. Welcome, welcome, welcome.”
Some of the girls looked tired and confused by all the attention after spending three years in captivity.
Before arriving in Abuja, they were brought by road convoy from a remote area to a military base in Banki near the border with Cameroon.
Our reporter says that many families in Chibok will be rejoicing at this latest news, but more than 100 of the girls taken have yet to be returned.
“This is good news to us. We have been waiting for this day,” Christian pastor Enoch Mark, whose two daughters were among those kidnapped, told Agence France-Presse.
“We hope the remaining girls will soon be released.” It was unclear whether his daughters had been freed.”
A statement from a spokesman for President Buhari earlier said he was deeply grateful to “security agencies, the military, the Government of Switzerland, the International Committee of the Red Cross, and local and international NGOs” for playing a role in the operation.
In a later BBC interview, presidential spokesman Garba Shehu added: “With all of these things together we negotiated over a period of several months, and at the end of it some of their (Boko Haram’s) members were exchanged for the 82 girls.”
‘Two blindfolded men in convoy’- The BBC’s Stephanie Hegarty reports from Lagos
Information about the release began trickling out on Saturday afternoon.
A soldier contacted the BBC to say that more than 80 Chibok girls were being held in an army base near the Cameroon border.
At the same time an official working for an international agency, who assisted with the release, said that several armoured vehicles left Maiduguri – the city at the centre of the Boko Haram insurgency – in a convoy to travel into the “forest” to meet the girls.
He said there were two blindfolded men in the convoy.
The president’s office said that the girls were released in exchange for some Boko Haram suspects held by the authorities – but we haven’t been told how many.
After the Government Girls Secondary School in Chibok, Borno state, was raided in April 2014, more than 50 girls quickly escaped and Boko Haram then freed another 21 last October, after negotiations with the Red Cross.
The campaign for the return of the girls drew the support of then US First Lady Michelle Obama and many Hollywood stars.
Last month, President Buhari said the government remained “in constant touch through negotiations, through local intelligence to secure the release of the remaining girls and other abducted persons unharmed”.
Many of the Chibok girls were Christian, but were encouraged to convert to Islam and to marry their kidnappers during their time in captivity.
Boko Haram has kidnapped thousands of other people during its eight-year insurgency aimed at creating an Islamic caliphate in north-eastern Nigeria.
More than 30,000 others have been killed, the government says, and hundreds of thousands have been forced to flee from their homes.
Boko Haram at a glance:
- Founded in 2002, initially focused on opposing Western-style education – Boko Haram means “Western education is forbidden” in the Hausa language
- Launched military operations in 2009
- Thousands killed, mostly in north-eastern Nigeria, hundreds abducted, including hundreds of schoolgirls
- Seized large area in north-east Nigeria, where it declared a caliphate
- Joined so-called Islamic State, now calls itself IS’s “West African province”
- Regional force has now retaken most of the captured territory
- Group split in August after rival leaders emerged