Several people were injured in a shooting at a high school in the southern French town of Grasse on Thursday, police said.

One person was arrested and another was on the run after the shooting at the Tocqueville high school, a police source told AFP, asking not to be named.

All schools in the town, some 40 kilometres (25 miles) west of Nice, have been locked down, education authorities said.

Interior Minister Bernard Cazeneuve cut short a trip to the northern Somme area because of the Grasse shooting, as well as a letter bomb blast at the offices of the International Monetary Fund in Paris on Thursday.