image captionMany parents who found their children after the attack quickly took them home
Hundreds of students are reportedly missing after gunmen raided a secondary school in north-western Nigeria.
The attackers arrived on motorbikes and started shooting in to the air, causing people to flee, witnesses said.
They targeted the Government Science Secondary School – where more than 800 students are said to reside – in Katsina state on Friday evening.
Police have not given a figure for how many students are believed to have been kidnapped.
Residents living near the all-boys boarding school in the Kankara area told the BBC they heard gunfire at about 23:00 (22:00 GMT) on Friday, and that the attack lasted for more than an hour.
Security personnel at the school managed to repel some of the attackers before police reinforcements arrived, officials said.
However, witnesses said they saw a number of students being carried away.
media captionInside abducted Chibok girls’ school in Nigeria
Several local residents on Saturday said they had joined the police in searching for hundreds of students who remained unaccounted for, while many parents said they had withdrawn their children from the school.
“The school is deserted, all the students have vacated,” one witness, Nura Abdullahi, told AFP news agency.
“Some of the students who escaped returned to the town this morning, but others took a bus home,” he added.
The army and air force have also joined in the search for missing students.
Katsina is the home state of Nigerian President Muhammadu Buhari, who is currently there for a week-long private visit.
The attack on Friday came two days after the kidnapping of a village leader and 20 others in another part of state.
In 2014, more than 270 girls were kidnapped by the militant Islamist group Boko Haram from a school in the north-eastern Nigerian town of Chibok.