Unidentified gunmen killed a student in an overnight attack on a boarding school in the north-central Nigerian state of Niger on Wednesday and kidnapped 42 people including 27 students, the state governor said.

The assailants stormed the Government Science secondary school in the Kagara district of Niger state at around 2 a.m., overwhelming the school's security detail, Governor Abubakar Sani Bello said.

"Twenty-seven students, three staff and 12 members of their families were kidnapped. Unfortunately, one student was shot dead," he told a news conference.

Aliyu Isa, a teacher, told local TV news station Channels that the abductors were dressed in army uniforms and shooting as they broke into the school.

"They were telling the students not to run," added Isa, who said he and others fled in the confusion while the gunmen rounded up some of the pupils.

It was not immediately clear who was responsible for the latest abduction. Kidnappings for ransom by armed groups are common across many northern Nigerian states.

The attack came two months after gunmen stormed a secondary school in northwestern Katsina state and kidnapped nearly 350 boys, who were subsequently rescued by security forces.

Rights group Amnesty International said in a statement that education is "under attack" in northern Nigeria.

"The Nigerian authorities must act immediately to prevent attacks on schools, to protect children's lives and their right to education," the group added.

Militant group Boko Haram also carry out abductions in Nigeria's turbulent northeast. About 100 of more than 270 schoolgirls abducted by Boko Haram from the town of Chibok in 2014 remain missing.

In the wake of Wednesday's attack, the Niger state governor ordered the immediate closure of boarding schools in the region.

President Muhammadu Buhari dispatched security chiefs to coordinate rescue operations, his spokesperson Garba Shehu said in a statement.

"President Buhari has (given assurance) of the support of his administration to the armed forces in their brave struggle against terrorism and banditry and urged them to do all that can be done to bring an end to this saga," Shehu said.

The Nigerian army said in a statement that it has mobilized troops who are pursuing the abductors. And the country's police chief said his force was working with the Department of State Security to reinforce security in the area where the abduction took place.

The recent attacks have raised concern about rising violence by armed gangs fueling criticism of Buhari's handling of national security. In January, the president appointed a new military high command.

Violence and insecurity have compounded the economic challenges faced by citizens in Africa's most populous country, which is struggling to cope with a fall in revenues due to an oil price slump on top of the COVID-19 pandemic.