A series of violent attacks on pupils at a Jewish Ort school in Paris have led to the organisation putting round-the-clock security measures in place at its five French schools.

Two attacks took place at the Daniel Mayer High School, run by the Jewish education charity, in the Paris suburb of Montreuil last week.

In the first, a small group of students were violently assaulted without warning near the school building by six attackers.

“They were severely beaten for no apparent reason and without the exchange of a single word,” an Ort France spokesman said.

One student, named Nathan, had his nose and teeth broken. Three others sustained slight injuries, including a Turkish pupil at the school who intervened to defend his friends. The attackers had left by the time police arrived.

The next day, a group of five men of “North African” appearance, one of them wearing a kefiyeh, verbally and physically abused a 17-year-old female Ort student as she waited for a friend at Porte de Montreuil Metro station.

“Inappropriate comments of a sexual nature were followed by her being shoved,” the Ort spokesman said. “When she cried out, one of her attackers said: ‘Shut up or we’ll throw you on the track and make you like Gaza!’”

In a third incident, security guards tried to detain a man in his 30s who was spotted on school premises. He ran away after telling the guards he was Muslim and that his presence showed security failures.

Private guards patrol the premises at all times, and French police have now stationed a guard outside the school during the day to protect its 844 Jewish and non-Jewish students.

The attacks are not the first against Ort students in France: there were several during the Second Intifada, as well as an arson attack on its Marseilles school in 2009. “The situation always becomes more tense when there is conflict in Israel,” the spokesman said.