Germany is investigating 30,000 suspects as part of a probe into an online paedophile network, the latest in a series of child sex abuse scandals that prompted authorities to promise a crackdown.
The probe began last October with the arrest of a suspected perpetrator in Bergisch Gladbach, near Cologne.
But investigators digging into the case have turned up a far bigger paedophile network than expected.
"I did not expect, not even remotely, the extent of child abuse on the internet," North Rhine-Westphalia's justice minister Peter Beisenbach told reporters.
What the investigation team had uncovered was "deeply disturbing", he said.
"We must recognise that child abuse on the internet is more widespread than we had previously thought."
The cyber crime office in North Rhine-Westphalia is now "investigating 30,000 unknown suspects" in the case linked to the city of Bergisch Gladbach, said Mr Beisenbach.
"We want to drag perpetrators and supporters of child abuse out of the anonymity of the internet," he added.
Those being investigated are suspected of sharing "child and youth pornographic content" including "fictitious and/or real acts of abuse" in anonymous online discussion forums and chat groups, the cyber crime office ZAC NRW said in a statement.
To date, just over 70 suspects have been identified throughout Germany.
In May, the first offender - a 27-year-old soldier - was sentenced to 10 years in prison and placed in a psychiatric hospital for an indefinite period.
Germany has been shocked at the discovery of several serious cases of child sex abuse over the past 18 months.
In early June, 11 people were arrested on suspicion of sexually abusing children and filming their actions after videos and photos were seized from the cellar of a 27-year-old man from the city of Muenster, also in North Rhine-Westphalia state.
Investigators said they had identified at least three victims, aged five, 10 and 12 years old.
Officials said then that investigative capacities on child abuse had been increased, which would likely lead to the discovery of more cases.
The case triggered calls from politicians to crack down on those using and sharing child pornography, with calls for it to be classed as a crime rather than just an offence.
"Child abuse cannot be punished like shoplifting. It is murder. Not physically but emotionally. Anyone who molests children must be punished as a criminal, fullstop," said North Rhine Westphalia interior minister Herbert Reul.
Justice Minister Christine Lambrecht in mid-June conceded offenders would in future receive a sentence of at least one year. "Anyone who commits such disgusting crimes must feel the full force of the law," she said.
In an earlier scandal in Luegde, 125 kilometres from Muenster, several men abused children several hundred times at a campsite over a period of several years.
Prosecutors said more than 40 children fell victim to the men at the "Eichwald" campsite between 1998 and 2018, most of them between three and 14 years old at the time.
Some 33 witnesses, including 16 victims and 12 relatives, testified before the court in the trial, many of them behind closed doors.
Child sex abuse was also placed in the spotlight when police announced in May they suspected a German man of having murdered missing British girl Madeleine McCann.
The 43-year-old suspect, named as Christian B. by German media, has a long criminal past and a history of child sex abuse.