More than 20 schools in France, Italy and Britain were placed on alert Thursday after receiving threatening phone calls, following a wave of hoax bomb scares earlier this week.

French education authorities said there were ‘no bomb alerts but threats’ at five of the most prestigious schools in Paris, without giving further details.

The schools were placed under police surveillance.

A French high school in Rome was evacuated as was a trilingual creche, after similar threats, according to letters sent to parents.

Meanwhile in Britain, police said they were probing threats at 14 schools in central England believed to be ‘false and malicious.’

‘At this stage there is nothing to suggest there is any credible threat to any of the schools,’ said Detective Inspector Colin Mattinson of the West Midlands police, the force that covers the city of Birmingham.

British media said four schools in London had been evacuated, although this was not confirmed.

The threats come two days after six Paris schools and 14 in Britain were evacuated following hoax bomb threats.

Those threats were claimed by a Twitter account calling itself the Evacuation Squad, with a profile picture of Russian President Vladimir Putin. The account featured previous messages in support of Syrian President Bashar al-Assad.

‘We are six individuals based internationally,’ reads the profile blurb, advertising its services to call in bomb threats.

The account has since been suspended.

Both France and Britain are on high alert after again being threatened by the latest Islamic State group propaganda video, released on Monday showing the jihadists who attacked Paris in November.

The IS group's French-language magazine Dar-al-Islam called in its November edition for its followers to kill teachers in the French education system, describing them as ‘enemies of Allah’.