French authorities say a high school where a teacher was fatally stabbed in an attack last week has been evacuated over a bomb alert, as France’s president cut short travel plans abroad to host a security meeting Monday.

The prefecture of the northern Pas-de-Calais region said the decision was made to evacuate the high school in Arras after police received a bomb threat via its website.

A demining team was on site, the prefecture said, adding that “all precautionary and safety measures” are being taken until the site is cleared

France is on heightened alert against feared terror threats following the stabbing incident.