More than 100 people have been charged with child sex abuse offences in Austria after police seized material from computers across the country.
Those arrested were aged 18 to 70 and included five teachers, officials said.
The 107 people arrested are accused of downloading images of child sex abuse from a server in Luxembourg.
A spokesman for Austria's federal investigations office told the BBC one of the suspects had collected more than 20,000 photos and 300 videos.
Alexander Marakovits said the investigation began a year ago after a tip-off from police in Luxembourg.
They informed Austria that more than 160 internet addresses traced to Austria were downloading material from a server being monitored by detectives.
Just 107 of the suspects could be traced, as some of those accessing the server attempted to cover their tracks, including by using internet cafes.
Mr Marakovits said one of the suspects was a nursery school teacher, and described the arrests as the second largest strike in Austria against people accessing such images.
In their biggest operation, last year, Austrian police charged nearly 190 men after breaking up a ring that spanned 170 countries.