Vienna - Four Austrian teenagers on Monday confessed to having attacked participants commemorating the liberation of a former concentration camp, an Interior Ministry official said.

The Austrian public and politicians were shocked about the incident at the Ebensee camp in Upper Austria province on Saturday, when the four reportedly fired plastic ammunition on a group of French visitors with a fake machine gun.

The masked 14- to 16-year-old male suspects also greeted a group of Italian participants with Nazi salutes of "Heil Hitler" and "Sieg Heil."

The gun attack took place in a tunnel that the inmates were forced to build by the National Socialist regime during World War II. Survivors were among the guests at the event commemorating the liberation by US forces in May 1945.

"They have confessed to a large extent," Upper Austria's top Interior Ministry official Alois Lissl told the German Press Agency dpa Monday evening. "They say they wanted to provoke."

Although they do not seem to be members of the neo-Nazi scene, they could be charged with breaking the country's ban on National Socialist activities, Lissl said.

They could also face charges of disturbing the peace of the dead, as the camp in Ebensee is considered a burial ground, Interior Minister Maria Fekter was quoted as saying by Austrian press agency APA.

The Catholic Church in Austria and various politicians expressed disgust about the incident on Monday. "Such provocations are unbearable and cannot be tolerated," Foreign Minister Michael Spindelegger said.

Of the 27,000 men from all over Europe who were deported to Ebensee, around 8,500 died of exhaustion or at the hands of Nazi SS forces.(dpa)