Aisha Alkali Wakil, a renowned human rights activist and lawyer based in the restive northeast region of Nigeria, said the Abu Musab Al-Barnawi faction of Boko Haram had contacted her on Thursday to confirm the custody of the schoolgirls.
According to Wakil, widely called Mama Boko Haram in Nigeria, "the girls are safe, healthy and in good condition."
She told the official News Agency of Nigeria that Al-Barnawi, the leader of that Boko Haram faction had promised not to harm the girls or kill them.
Earlier this week, the renowned human rights activist had identified the abductors and openly pleaded with them to release the schoolgirls.
She said the Boko Haram faction called her in respect of her prayer.
Further disclosing details of her conversation with the Boko Haram faction, Wakil said she begged them not to keep the schoolgirls in custody for long as they did in the case of the Chibok schoolgirls kidnapped in 2014.
Wakil said she was ready to sacrifice her life to rescue the girls from their abductors, also pledging her renewed commitment to seeing the end of Boko Haram's terror attacks.
In the past, she had earned credits for the release of some abductees from the Boko Haram group via phone calls to the leadership.
The United Nations believes Boko Haram has killed more than 20,000 innocent people since 2009 through terror attacks.