A major fire has broken out at a chemical plant in northern Italy, with authorities on public health alert.

The factory is located in Novara, in the region of Piedmont.

Strong forces of the Fire Department are at the scene, while a large black cloud of smoke has spread over the area.

The mayor of the city of San Pietro Mosezzo is appealing to residents to stay indoors and children to remain in their classrooms at schools, with windows closed as the entire area is cordoned off and their parents cannot pick them up.

The authorities have ordered the evacuation of homes within a radius of 500 meters around the Kemi Srl factory as there is a risk of the fire spreading. Eyewitnesses report that explosions are constantly heard and the flames exceed 50 meters.