The man said the school would be blown up in one hour, and police proceeded to evacuate 85 teachers and more than 700 students from the building.
Specialists from the rescue department arrived at 11:30 a.m. and examined the school building. No bomb was found.
The police said only three digits of the caller's telephone number were identified. He likely called from Narva's fixed-line telephone network, police believe.
According to the department, the call was seriously considered only because of the fact that an adult had made it.
Due to frequent false bomb alarms that have occurred this year, the department does normally not react on calls made by children.
One of the reasons for the threat might have been that the director of the school and City Councilman Arno Timoshkin, supported a no-confidence vote against Efendiev on Oct. 26.
Timoshkin declined to comment.
Ex-Mayor Efendiev of the Center Party may still remain in the Narva government but only as a member of the City Council.