But around 253 of the kidnapped children, along with 12 staff members and teachers, are still with the kidnappers, said the Catholic Church and Christian Association of Nigeria chairman Bulus Yohanna, a Catholic Bishop who is also the proprietor of the school.
Yohanna said the pupils escaped on Friday and Saturday. Parents rushed to the school in Niger state, to the west of the capital Abuja, after hearing that some children were free.
Amose Ibrahim was one of the parents who went to St Mary's school to check if any of his three children had escaped.
"Unfortunately, they were not among the escapees," Ibrahim, whose youngest child is six, told Reuters by phone.
"As of now, many parents and their loved ones are roaming around the school."
President Bola Tinubu ordered the hiring of 30,000 more police officers at a meeting with security chiefs on Sunday.
He directed the removal of all police from VIP protection services to focus on core duties, especially in remote areas prone to attacks.
Nigeria faces scrutiny from US President Donald Trump who earlier in November threatened military action over the treatment of Christians in the country.
Gunmen kidnapped students and teachers from the school on Friday, the latest in a spate of school attacks that has forced some northern states to shut schools. The government also ordered the closure of 47 colleges in the north.
Pope Leo pleaded on Sunday for the immediate release of those who had been taken in one of the worst mass kidnappings ever recorded in Nigeria.
"I make a heartfelt appeal for the immediate release of the hostages," the Pope said at the end of a mass in St Peter's Square in Rome.
In a separate incident, Tinubu said Nigerian security forces on Sunday rescued 38 people who were abducted during a service at Christ Apostolic Church in Kwara state. At least two people died during the attack.
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