A social media alert was issued after many students of a UK school received a shocking video showing a teenage girl sexually abusing a six-year-old boy.

The head teacher of the school in Kent, England said that the video, suspected to have been filmed in the US, has gone viral in their academy. It has been viewed at least 20,000 times in five minutes, Principal Mary Boyle of Knole Academy in Sevenoaks, said according to KentLive.

She added that the video was circulated through Snapchat and Instagram among students, one of whom alerted her about it.

Boyle told the paper that the video was sent to the students' social media accounts on Monday (4 December) afternoon. She added that police has been informed and an investigation is underway.

Speaking about the shocking incident, Boyle said, "It would appear the incident took place in the United States of America. The British police are investigating the distribution of the video.

"We are very grateful that one of our students came into school this morning and informed us of the video and allowed us to quickly contact the police."

Boyle has also issued a letter to the students' parents, urging them to check their childrens' social media profiles to see if there are any links connected to the post and delete if they find any. "We will be reinforcing the message in assembles throughout the week," the principal added.

She also said that strict guidelines are in place in their school on social media usage and students have been told what to do if inappropriate sexual behaviour was shared online.

"It is made clear that this is an illegal activity. We commend the young person who gave us the information and would advise all young people to tell an appropriate adult when they are aware of these issues," she said.

Meanwhile, a Kent Police spokesman confirmed the news and added that specialist officers were probing the origin of the video and if any crime has been committed locally with regard to the video.

"Kent Police is aware that a video file containing inappropriate and explicit material has been widely circulated in the country on social media and seen by a number of young people. Officers are advising anyone that receives the file to delete it and not to forward or share as this may constitute a criminal offence," the spokesman said.

"Kent Police has received a number of calls about the file and is looking to establish whether any offences have been committed locally."

A spokesman for child protection charity, NSPCC (National Society for the Prevention of Cruelty to Children), told KentLive that the availability of such sexual abuse material online was posing a growing threat to child protection.

"It is extremely concerning that in this case this sickening material has seemingly been viewed by children and young people and circulated between them on social media," the person noted, adding that they have been urging the government to take tighter actions to prevent child sex abuse and distribution of such material online.