Many of the hundreds of children kidnapped from a Catholic school in Nigeria were as young as 5 years old, according to a nun who also described how 50 of the students escaped over the weekend.

Mary Barron, the superior general of the Missionary Sisters of Our Lady of Apostles (OLA), described many of the 303 children kidnapped from St. Mary's School in Nigeria’s Papiri community on Friday as "tiny," the 50 children escaped their captors by jumping over a wall and running into the bush.

"They said they walked and walked, because they knew they couldn't walk back to the school, so they just kept walking until they found something familiar," she said.

No group has come forward to claim responsibility for the attack, The Associated Press reported. The outlet added that authorities said tactical squads and local hunters were working to rescue the kidnapped children.

It remains unclear where the remaining students and teachers were being held.

"I really keep hope alive," Barron said. "I really believe if there is a concerted effort, if we get enough people mobilized with the resources necessary to try to find these children, then it can happen."

Nigeria has seen a series of attacks on Christians and their institutions, prompting President Donald Trump to declare the West African nation a "country of particular concern." However, the Nigerian government has disputed the U.S. claims.

Fox News Digital’s Rachel Wolf and Anders Hagstrom, along with The Associated Press, contributed to this report.