Six people were arrested and weapons seized after violent disorder erupted on a city seafront and high street, police said.

Essex Police said a Section 60 dispersal order will remain in place in Southend-on-Sea until 20:00 BST on Wednesday after the disorder on Tuesday night.

It comes after a video shared on social media appeared to show at least four people dressed in black brandishing what appeared to be large knives near the resort’s Adventure Island theme park.

Police said investigations into the incident were ongoing. The area appeared clear at 06:30 BST on Wednesday.

David Burton-Sampson, the Labour MP for Southend West and Leigh, warned people to “keep away” from the area.

The disorder began at about 19:00 on Tuesday with large crowds of young people seen on the Southend’s seafront, which had been busy on the UK’s hottest day of the year.

Members of the public were dispersed from the area by about 23:30, prompting additional police patrols in the city overnight.

Essex Police said it was “continuing our investigations into the incidents of disorder in the city this evening, with several lines of enquiry to identify further suspects in addition to the six people arrested”.

A Section 60 order allows a constable in uniform to stop and search any pedestrian or anything carried by them, as well as vehicles, for offensive weapons.

It covers areas such as Marine Parade, Pier Hill, High Street, Western Esplanade and both the city’s train stations.

“We have a zero-tolerance approach to violence, disorder and carrying weapons in Essex,” Chief Supt Morgan Cronin said.

The force said “while our work is ongoing there will be a large and visible police presence across the city centre, and further disorder will not be tolerated”.

Previous dispersal orders have been put in place in the city in response to concerns about the behaviour of groups of young people who have gathered on the seafront.

At the scene – Lewis Adams, BBC Essex

“The seafront at Southend-on-Sea is a much quieter place this morning than it was last night.

“People were seen fleeing from outside Circus Amusements when things turned ugly at the heart of the city.

“All that remains from the frantic scenes that circulated on social media on Tuesday evening are bags of discarded litter.

“This area is so close to Southend Pier that visitors, including families with children, flock to it in their droves throughout the year.

“We can expect a much busier seafront carefully patrolled by police as the sun comes out later on.”

Daniel Cowan, Labour leader of Southend City Council, said there had been a “large influx of young people”.

Mr Cowan told BBC Essex: “Firstly these were extremely upsetting scenes for our city.

“We know that a large number of youths came to Southend with intent to behave in this deplorable manner.

“It is unclear how many of them came in a ‘spur of the moment’ thing.

“It is deeply concerning.”

Mr Cowan said he was working with Essex Police to understand the cause of the disorder.

“We do to want this kind of behaviour in Southend and we want to stop people like this travelling to Southend,” he added.

“We need to learn how to stop these coordinated events.”

Essex Police thanked “the vast law-abiding majority of the public for their co-operation” and asked witnesses to come forward.

Anyone with information or dashcam footage of the disorder has been asked to contact the force on its website or by calling 101, quoting incident number 1094.