Child sexual abuse streamed live over the internet on services like Skype has been flagged as an emerging threat by experts.
An increasing number of offenders in 2012 were seen targeting vulnerable families overseas to set up live access to children over webcams in exchange for payment, the Child Exploitation and Online Protection Centre (Ceop) has found.
In its annual threat assessment of child sexual exploitation and abuse, Ceop also warned that there are increased fears of child sexual abuse in Brazil as more visitors head there over the coming years for the World Cup and Olympic Games.
In 2012, Ceop received 8,000 reports of indecent images of children being shared, featuring a two-fold increase in the number of images and videos on previous years to 70,000.
Ceop chief executive Peter Davies said: "Our assessment shows that, sadly, there are still too many children at risk and too many people who would cause them serious harm. We should all practice zero tolerance to child sexual exploitation and abuse."
Live streaming was identified as an emerging method of producing and distributing indecent images last year, the report said.
And Ceop warned that this tactic - particularly in the developing world - continues to carry a high risk this year.
Sex offenders are targeting families and children in areas with extreme poverty, rising levels of access to the internet and poor child protection policies, the report said.
The centre also raised concerns about the use of the so-called hidden internet - heavily encrypted forums and pages that allow abusers to cover their tracks when accessing indecent images online.
UK daily users connecting to secret or encrypted networks increased by two thirds, one of the largest annual increases globally, the report said, with 20,000 daily UK users of such networks expected by the end of this year, although not all of these will use the hidden internet for criminal means.
Meanwhile, Ceop found that there has been a 70% increase in the number of female victims under 10 years old.
The report comes shortly after after five members of a seven-man sadistic paedophile ring found guilty of grooming vulnerable underage girls were given life sentences at the Old Bailey. Two other defendants were both jailed for seven years.
Ceop said that a number of offenders have been identified as targeting teenagers and young adults on the basis of their vulnerability rather than due to a specific sexual interest in children. These are known as "type one" offenders and crimes.
And figures from police forces show that the majority of type one offenders were categorised as Asian, and 97% of type one offences involved white victims.
But figures from 25 police forces revealed 2,120 lone perpetrators and 31 forces reported 65 group or gang related offences.
An NSPCC spokeswoman said: "The evidence the NSPCC has gathered from all police forces in England and Wales shows there are around 20,000 sexual offences against children reported every year and many of the victims are under primary-school age.
"However, we believe this is far from the true situation as many cases are never revealed. And since the Savile sex crimes were revealed, our helpline has experienced an increase in the number of adults reporting cases which happened many years, even decades, earlier.
"While there are cases of children being sexually assaulted by strangers, the vast majority of these offences - around nine out of 10 - are committed by someone the child knows.
"It is crucial that our efforts to protect children from sexual abuse focus on deterrence and prevention and that our focus is the risk to children, both on and offline."