Three men were stabbed at a popular holiday resort hours after a major incident was declared when thousands of sunseekers flocked to beaches amid the heatwave.
The men, all in their 20s and from London, were hurt during a fight near the amusements on Bournemouth pier on Thursday evening.
The three men were taken to hospital for treatment by the ambulance service.
Dorset Police said one man sustained a stab wound to his back and has since been discharged from hospital.
A second man sustained an injury to his face and the third was injured in the chest and arm.
Their conditions are not described as life-threatening.
Detective Inspector Gavin House, who is leading the investigation, said: “We are carrying out a full and thorough investigation to determine who was responsible for this incident.
“The public can expect to see an increased police presence near to the pier today as detectives continue their inquiries in the area.
“I understand there was a large number of people on the beach at the time of the incident and I would urge anyone who may have important information to assist my investigation to please get in touch.
“I am keen to hear from anyone who may have video footage of the incident and would please ask that you do not post or share this online out of respect for the injured people.”
Meanwhile, council and emergency services have praised local people for showing restraint after the major incident was declared.
Extra police patrols have been brought in and security is in place to protect refuse crews who the council said faced “widespread abuse and intimidation” as they emptied overflowing bins.
Over 50 tonnes of waste has been cleaned up from the promenade and beaches in just one day.
Council leader Vikki Slade said: “Local people have been brilliant and I would like to pass on my sincere thanks to them for listening and obeying the warnings issued.
“We know so many of you share our frustrations at what happened over the last two days on our beaches.
“This is about outside visitors coming into the area in their thousands and refusing to take responsibility for their actions.
“We are still in a pandemic and in lockdown. When it became clear that an unsafe situation was emerging, we followed the official emergency planning process in place allowing us to escalate and take a multi-agency response to manage the issues on the ground.”
Bournemouth East MP Tobias Ellwood said 500,000 people had visited Dorset and added his voice to the calls for people not to go to the area.
“This place was deluged and social distancing went out the window and that’s why a major incident was declared, because the local authority and indeed the police couldn’t cope,” he told BBC Breakfast.
“The beach should have been closed down, or at least shut down to prevent further people from entering it.
“We need to learn from this and recognise that if we’re going to be serious about tackling this pandemic then we need to be swifter in being able to provide support to local authorities who are unable to cope.”
After a second night of disorder in Exmouth, another dispersal notice has been issued for the weekend, from midday on Friday to midday on Sunday.
Superintendent Antony Hart said: “These reports have included large groups of young people and adults fighting, a serious assault and officers being verbally abused and spat at.
“Needless to say, this is absolutely unacceptable behaviour and it will not be tolerated.
“Anyone who is formally given notice to disperse from the area must not return within the notice period and anyone who does is liable for arrest and prosecution.
“While we want people to be able to have a good time and enjoy themselves, drinking to excess and meeting in such large groups is putting themselves and many others at risk.”