Emails “threatening violence to children and staff” have been received by a number of schools in Leeds.
West Yorkshire Police has launched an investigation – with officers “providing reassurance and safety advice to affected schools”.
In messages to parents, one primary headteacher said police had been treating the threat as “credible” – and children were being kept indoors for the whole day, with gates locked and windows and doors closed.
Earlier this week, a police investigation was launched after malicious emails were sent to a number of schools in the North West.
One parent told Sky News that she was “petrified” after she was told – and that it reminded her of incidents affecting schools in the US.
A school in Chester went into lockdown and prevented parents from picking up their children – but later said the “unpleasant email” it had received was “believed to be a malicious hoax”.