Some 300 schools across Italy have received bomb threats, according to Education Minister Giuseppe Valditara, who described the incidents as probably a "cyber-attack, not a genuine risk".
Valditara told Italian TV that there was a clear strategy behind the rash of threats in Italy and elsewhere in Europe which had targeted flights, supermarkets and even hospitals.
The emails were sent to schools in Rome, Naples, Vicenza, Florence, Pisa, Trieste and many other Italian cities, and a number of buildings were evacuated as a precaution.
Prime Minister Giorgia Meloni has called a meeting of top ministers and intelligence chiefs.
Meloni said the government was monitoring closely the "numerous reports of bomb threats at educational institutions" although checks so far had not indicated any evidence of "concrete danger".
"These reports appear rather linked to a strategy intended to cause alarm and concern," she said on Facebook.
Italian airports along with airlines elsewhere in Europe were hit by a series of bomb hoaxes last week that prompted a series of scares, evacuations and widespread disruption. Although a number of threats were claimed by an extremist misogynistic group, it later denied any link to the false warnings.
Italian reports said 280 school head teachers had received threats in recent days.
Although many schools were initially evacuated on Wednesday, the alarm was quickly lifted, according to reports from a number of regions, and pupils were allowed to return to class.
In a statement, the head of the central Umbria region Stefania Proietti said "checks conducted so far in Umbrian schools have proved negative, and law enforcement is working rapidly and carefully to verify each report".
In a separate incident, more than 300 schools in Northern Ireland were sent emails which police said they were treating as a hoax. Messages sent to number of schools in Scotland were also being treated by police as a hoax. It is unclear whether any of the incidents are connected.
