Schools across Italy have received bomb threats for the second day in a row, sparking fresh panic and evacuations.

Some 3,778 schools, from Milan in the north to Sicily in the south, reported similar threats to one that created chaos on Wednesday – even though no explosive devices have been found.

The government has advised schools that “in the absence of concrete evidence beyond the simple receipt of a mass email indicating a danger, buildings must not not be evacuated”. Unlike a day earlier, only 77 schools were evacuated on Thursday, authorities say.

Prime Minister Giorgia Meloni says her government will come up with “sector-specific” advice to help those facing this kind of threat.

Schools in Scotland and Northern Ireland received threats on Wednesday, too. It is unclear whether the incidents are connected.

On Thursday morning, a bomb alert at a Calais rail station delayed international and national train services in northern France.

The latest incidents follow a series of bomb hoaxes last week against airports and airlines in a number of European countries.

Although a number of threats were claimed by an extremist misogynistic group, it later denied any link to the false warnings.

Wednesday’s email threat – sent to 6,300 out of a total of 7,476 Italian state schools – was said to be from a certain “Mikhail Andropov, leader of Vilayat di Misoginistan”.

Some officials say it originated in Taiwan.

A similar message sent to Italian schools on Thursday, again signed by Mikhail Andropov, is said to have been sent from the account of a teacher in the Philippines whose account is believed to have been hacked.