DCI Steve Thubron, of Durham Police, said: "We record incidents in line with national crime recording standards, which we cannot deviate from. However, we deal with incidents proportionately and obviously do not criminalise children.
"Cases of 'sexting' are dealt with on a case-by-case basis with the focus always being on safeguarding and keeping children safe.
"We have worked with other agencies to provide advice and guidance to both schoolteachers and young people. We would urge any children who are worried to speak with a trusted adult."
More than 4000 children in the UK have been dealt with by police for sexting since 2013. The most common age of these children is 13 or 14, figures show.
The latest statistics have emerged from a Freedom of Information request to all UK police forces in an investigation by BBC Newcastle.
A 10-year-old boy, only just at the age of criminal responsibility, has also been cautioned by Northumbria Police for sexting.
The boy sent a sexual image of himself to an 11-year-old child using Oovoo, a free social media video and image sharing app.
Greater Manchester Police recorded the highest number of child sexters with 695 cases looked into, including four 7-year-olds and four 8-year-olds.
It is illegal in the UK to possess, take or distribute images of someone who is under the age of 18, even if the image is of yourself.