It comes after a disturbance at a kabaddi tournament in Alvaston, near Derby, where four others were injured and taken to hospital.

Those arrested, all men aged 24, 28, 30 and 38, have been detained on suspicion of possession of a firearm and violent disorder, and remain in police custody.

Videos on social media show groups of men covering their faces and entering the venue on Elvaston Lane with weapons - with at least one carrying what appears to be a sword.

In one clip, the group appears to be marching in together to attack another group of people.

Another video appears to show crowds running away from what is thought to be gunshots, before being greeted by men wielding what looks like knives.

More footage shows dozens of police cars surrounding the venue.

The tournament was being broadcast online, with pictures showing the moment commentary stops as people watching begin running away.

Speaking to the Daily Mail, one witness said a man was shot and "repeatedly" attacked with a sword, while others said the incident was caused by gang violence.

Some were unable to reach their vehicles, sources told the newspaper, adding many dashed away from the venue while giving their details to police.

Armed police were called to the venue on Sunday just before 4pm and remain on the scene.

Derbyshire Police Chief Superintendent Emma Aldred said: "We are keen to speak to anyone with information relating to the incident yesterday.

"We are aware of videos of the incident circulating online, we are carrying out investigations in relation to these and I would encourage anyone with footage to send it to us for enquiries to continue.

"Officers remain in the area to provide reassurance to the community, please speak to them if you have any information or contact us using the methods provided."

Kabaddi is a sport hailing from India, which is played by two teams of seven, which sees one player try to run into the opposing half and touch as many of the opposition as possible in 30 seconds, without being tackled to the ground.