The boy, who is said to have been armed with three guns and two grenades, launched the attack at Tocqueville high school, where he was a student.

Police say the headmaster seems to have been a target, and is among the injured.

Anti-terrorist commandos from the elite Raid force were sent to the scene.

Regional president Christian Estrosi said the "precise circumstances" around the shooting remained unclear, amid a number of conflicting reports.

One student reported hearing four gunshots, while another student, speaking to Nice Matin (in French), described hearing three loud bangs before turning and seeing a shooter.

At least two people were injured, one reported to be the school's headteacher

The government minister for victims affairs, Juliette Meadel, said via social media that all students were safe, adding her thoughts were with the parents of the two people injured in the attack.

It is still not clear how many shooters there were. Initially, local media said there was a second shooter who was on the run, but many outlets have now reported that there was only one.

Interior ministry spokesman Pierre-Henry Brandet told BFMTV: "We are still in the phase of rescue, of searching for a possible second perpetrator."

 It is unclear how many people took part in the attack

Despite the interior ministry issuing a terror alert, it does not appear the attacker has links to any extremist groups.

Grasse, the capital of France's perfume industry, is about 44km (27 miles) from the city of Nice, where a lorry attack in July killed 86 people.

France remains under a state of emergency after a string of deadly attacks in the past 18 months.