The freed girls and others still in captivity were abducted from the Kautikari community earlier this month in the Chibok Local Government Area.
In a statement by the organisation on Monday, UNICEF expressed relief over the girls’ freedom on Sunday.
“UNICEF is very relieved for the released girls and their families,” UNICEF representative in Nigeria, Peter Hawkins, said.
He continued, “After their harrowing experience, it is good news that the girls are back with their families and friends, where they belong.
“But sadly, dozens of children in north-east Nigeria remain in captivity; the victims of an armed conflict they have nothing to do with. This is unconscionable.
“Children have the right to a safe environment, health, education and freedom from abuse and torture – all of which remain compromised when they are in captivity.”
In 2014, Chibok gained global attention after 276 schoolgirls were abducted in the area.
According to UNICEF, about 173 of the Chibok girls were still missing. In January, many were also abducted in Pemi, another community in the Chibok LGA.
Condemning the kidnap and calling for their release, Hawkins said, “Children are not the spoils of conflict. All children in captivity must be immediately and safely released to their families.”