The Nigeria Union of Teachers called an open-ended strike from Monday in the state of Oyo, in protest at the kidnapping in mid-May of dozens of children and their teachers.
On May 15, gunmen who Nigeria's army accused of being Boko Haram terrorists abducted pupils and staff from three schools in the southwestern state of Oyo.
Kidnappings for ransom are an ongoing battle for authorities in northern Nigeria, but the mass abductions were unusual for Oyo, one of Nigeria's most populous states.
Seven teachers were kidnapped along with between 25 and 39 children aged two to 16, officials said.
The search is still ongoing to find them.
‘Withdraw services’
The NUT urged primary and secondary school teachers in Oyo State "to withdraw our services from schools" from Monday "till further notice".
The union said the strike was in protest "against the continued detention of our colleagues and learners by the abductors without any clear sign of their timeous rescue and safe release".
The situation, it said, has "created fear and hopelessness in teachers, discouraged parents from sending their children to schools, and caused panic and tensions across all communities in the state".
It urged the government "to intensify strategies towards bringing the abductees back safely and without any further delay", advising teachers to stay at home and "remain law-abiding".
Schools raided
The gunmen simultaneously raided Baptist Nursery and Primary in the community of Yawota and two other schools in nearby Esiele in what police said was a "coordinated attack".
The Christian Association of Nigeria said 39 children and seven teachers were abducted from the schools, while the state governor said 25 pupils and seven teachers were taken.
The Nigerian army, in collaboration with the US military, has stepped up operations against terrorists in the north of the country, apparently forcing some to flee southwards.
On Sunday, President Bola Tinubu said 1,000 forest rangers were being recruited in Oyo State, and he was sending a "high-level" delegation there comprising government ministers and the national police inspector general.
