(CNN) Her face etched in pain and her grief palpable, the mother of one of the missing Chibok girls sunk to her knees and begged for the safe return of her daughter.
Rebecca Samuel Yaga was one of dozens of parents of the Chibok schoolgirls who attended an inaugural lecture Friday to commemorate the three-year anniversary of their kidnappings.
Boko Haram seized 276 students from the Government Girls Secondary School in Chibok on April 14, 2014. Fifty-seven managed to escape almost immediately, while two others were found by the army.
Chibok girls seen in proof-of-life video
Twenty one girls were released in October 2016 following negotiations in a deal brokered by an unnamed Swiss contingent and Nigerian authorities. Those negotiations are ongoing to free the remaining girls, the government said.
"The government is in constant touch through negotiations, through local intelligence, to secure the release of the remaining girls and other abducted persons unharmed," Nigerian President Muhammadu Buhari said in a statement Thursday.
"On this solemn occasion, my appeal is that we must not lose hope on the return of our remaining schoolgirls."
The lecture held at Abuja was one of a series of events and rallies held Friday to remember the 195 that are still missing. It was given by the Emir of Kano, Muhammed Sanusi, and was organized by the Bring Back our Girls group, which has long campaigned for their safe return.
Oby Ezekwesili, a co-founder of the movement, vowed Friday that they would continue to protest until the rest of the Chibok girls are brought back.
In Chibok, about 100 parents gathered at the secondary school for a multi-faith meeting with Muslim and Christian clerics to hold prayers for the safe return of the missing girls.
It was the first time the parents had met at the school to hold a prayer session since their daughters were kidnapped.
Yana Galang, the women's leader of the association of Chibok girls, told CNN: "Only a few parents got their daughters back. Over 100, including myself and my husband, are still groaning for... those who were not found."