The four boys attended the Schlossstrasse middle school in Salzburg. It was only in the wake of the widely reported New Year sexual assaults in Cologne that one of the victims, aged 14, made a complaint to police.
That resulted in the four youngsters, aged 14, 15 and 16, being suspended. Only one of them had a residence permit.
According to a report in the Kronen Zeitung newspaper, three female students say they were assaulted and groped by the boys for months.
Last Wednesday an attack on one girl was reportedly so severe that it came to the attention of the school headmistress Eva Szalony, who made a complaint to police.
She said the allegations were "a complete shock" and that the school is now investigating why the girls had suffered for so long without reporting the abuse.
She said that the male pupils had all come to Austria as unaccompanied minors from Syria and Afghanistan and she believed them to be happy and grateful for being allowed to live in Austria and attend school, adding that "they were integrating themselves very well".
Police have now confirmed they are investigating allegations of sexual assault, grievous bodily harm and threats.
The allegations go back to last November, and involve verbal abuse and suggestive comments as well as physical violence in which the girls say they were groped and fondled.
The attacks got more serious as time went by. The 14-year-old said that she was often hit by a 15-year-old from Afghanistan, including an incident where she was hit so badly from behind that she smashed her head onto the desk.
She was attacked again on Wednesday by the same boy, who smashed her against a locker so hard that the police were called. They took the victim and the accused to the station. After hearing of her ordeal, police then expanded the investigation.
Local education officials in Salzburg have said the incidents are being dealt with very seriously and that it will appoint a coordinator to oversee all school-age asylum seekers and their teachers.
Psychologists are now speaking to affected pupils in the school as well as their classmates, and parents have been informed about the situation.
Story courtesy of Central European News