Six people have been arrested as part of an “ongoing incident” in Southend-on-Sea.
Essex Police said they were detained earlier this evening in relation to “disorder”.
The arrests came as David Burton-Sampson, the Labour MP for Southend West and Leigh, warned people to “keep away” from the area.
Essex Police said it expected to have a visible presence in the area over the next two days.
On Tuesday, Essex Police put a dispersal order in place on Southend seafront. It gives officers more powers to tackle anti-social behaviour (ASB).
The order remains in force until 20:00 BST on Wednesday and covers areas such as Marine Parade, Pier Hill, High Street, Western Esplanade and both the city’s train stations
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.
Chief Supt Morgan Cronin said: “Our officers have responded to these incidents reported by members of the public this evening, and the information they provided is invaluable.
“We will have a visible presence in Southend this evening and tomorrow – if you know something, please speak to one of our officers or contact us to help.”
Daniel Cowan, Labour leader of Southend City Council, said there had been a “large influx of young people”.
Writing on his Facebook and X accounts, he said: “I’m urging calm and encouraging people to avoid Jubilee beach this evening as Essex Police deal with a large influx of young people.
“It’s a developing situation that CCTV and the police are monitoring and more police resources are en route to support the dispersal order that is in place.”