MINNA, Nigeria — A total of 100 of the schoolchildren abducted from a Nigerian Catholic school last month have been released, the Christian Association of Nigeria said Monday, adding that more than 100 students remain in captivity.

At least 303 schoolchildren were seized at the Niger state school together with 12 of their teachers when gunmen attacked the St. Mary’s Catholic School in Papiri community on Nov. 21. Fifty escaped in the hours that followed.

Daniel Atori, a spokesman for the association in Niger state, told The Associated Press that the church learned the children were released during the weekend and that they will be transported to Niger state’s capital of Minna to meet with officials.

It was not immediately clear how the 100 schoolchildren were freed or if any arrests were made. No group has claimed responsibility for the abductions but locals blamed the armed gangs that target schools and travelers in kidnappings for ransoms across Nigeria’s conflict-battered north.

The Niger state attack was among a spate of recent mass abductions in Nigeria, and happened four days after 25 schoolchildren were seized in similar circumstances in neighboring Kebbi state’s Maga town, which is 170 kilometers (106 miles) away. A church in the southern Kwara state was also attacked around the same time; the 38 worshippers abducted in that attack last month have been freed.

Under pressure at home and from U.S. President Donald Trump — who has alleged that Christians are being targeted in Nigeria’s security crisis — Nigerian President Bola Tinubu has promised he will not relent until all hostages are freed.

Nigerian authorities usually do not say much about rescue efforts and arrests in such cases are rare. Analysts believe that’s because ransoms are usually paid. Officials do not admit payment of ransoms.