Information minister Lai Mohammed said in a statement that "the girls were released around 3 a.m. through back-channel efforts and with the help of some friends of the country"
He added that the release was unconditional.
110 girls were taken on the night of 19 February from the government-run boarding school.
“A convoy of vehicles returned the girls this morning,” Bring Back Our Girls spokesman Sesugh Nkume told RFI.
“The Nigerian military was present and the handover was calm,” he said
Parents in Dapchi also confirmed the return of the children. There are reports that five of the girls are dead.
The kidnapping of the Dapchi girls game nearly four years after 276 girls were taken by Boko Haram from a boarding school in Chibok.
More than 100 of those girls are still missing.