Finland Panic spread among students in Finland on Thursday as threatening text messages and Internet postings raised fears of new attacks mimicking a deadly school rampage.
Worried children and parents jammed telephone help lines and scores of children stayed away from class after threats popped up against schools and students.
While most appeared to be hoaxes, police were taking every threat seriously to avoid a repeat of Tuesday's shooting, in which a 22-year-old gunman killed 10 people and himself at a vocational school in western Finland.
It was the second school shooting in the country in less than a year. Last November, an 18-year-old man fatally shot eight people and himself at a high school in southern Finland.
"It's clear that the more you talk about these incidents, the more chances there are of copycats," National Police Commissioner Mikko Paatero told reporters in Helsinki. "After we've witnessed two such incidents, the threat is real."
Similarities between the attacks - including reports that they bought their guns at the same place - prompted police to probe potential links between them.