Armed police were deployed to the centre of Broadstairs following a disturbance.
Officers arrived in the high street at about 5.10pm yesterday and seized a bladed weapon.
An investigation into the incident is underway but no arrests have yet been made.
It is reported four or five people assaulted a second group and then left the scene.
Detective Inspector Vanessa Law said: "An investigation is underway and we are appealing for any witnesses to call the appeal line.
"We also understand some people in area may have mobile phone footage of the incident and we are urging them to contact us.
"Motorists with dashcam and businesses or residents with private CCTV are also asked to check for footage that may assist our enquiries."
Anyone with information should call Kent Police on 01843 222289, quoting reference 46/111715/22.