- Around 150 students are missing after armed men attacked a school in northwest Nigeria's Kaduna state, a parent and an administrator told Reuters on Monday.
Armed groups who authorities say are after ransom payments have in recent months targeted schoolchildren across the northwestern part of Africa's biggest economy and most populous nation.
Islamist groups Boko Haram first carried out such kidnappings in 2014 in the northeast, but armed men, known locally as bandits, have recently adopted similar tactics.
They have taken around 1,000 people from schools since December.
Here are details of other attacks:
* Gunmen kidnapped 94 students and eight staff in a daytime school raid in northwestern Kebbi state on Jun. 17, police, residents and a teacher said.
Three children died while another eight, along with three teachers, were rescued, but the others remain missing.
* One student was killed and at least 10 people were kidnapped in an armed attack on the main campus of the Nuhu Bamalli Polytechnic in Zaria, Kaduna state, late on June 10 according to state authorities.
* Armed men abducted 136 students from an Islamic school in Tegina, a town in the north-central Nigerian state of Niger on May 30, a state official said. The students remain missing.
*Gunmen killed one person and took 19 captive in an April 20 attack on Greenfield University in Kaduna state. The bandits later executed five students before releasing the remaining 14 on May 29.
* Gunmen on motorcycles kidnapped three teachers from a primary school in the Birnin Gwari local government area of Kaduna on March 15, a state government official said.
* Gunmen stormed the Federal College of Forestry Mechanization on the outskirts of the Kaduna state capital on March 11, taking around 39 students.
The men released all the students by May 5. The chairman of the parents' association said a ransom was paid.
* Bandits kidnapped nearly 300 girls from the Government Girls Science Secondary School in Jangebe, northwestern Zamfara state in the early hours of Feb. 26, the state governor said.)
Gunmen beat them and threatened to shoot them, the girls said after their March 2 release.
* An armed gang in north-central Niger state killed one student and abducted 42 people, including 27 students, from the Government Science Secondary School in the early hours of Feb. 17, the state governor said.
All 42 captives were released on Feb. 27, state officials said.
* Gunmen kidnapped 344 boys from the Government Science Secondary School in the northwestern state of Katsina during a night-time raid on Dec. 11, state officials said.
Security forces rescued the boys, who said they had been held in a forest by the criminal gang, on Dec. 18.