Worthing Pier and seafront has been closed down after the discovery of a 'hazardous material'.
Sussex Police said a cordon had been set up along the seafront between Grand Avenue and Windsor Road, and people were advised to shut all windows and doors, or stay away from the area.
A small number of people have reported symptoms including sore eyes and vomiting, said the spokesman.
Read eyewitness accounts from the scene here: Worthing seafront evacuation: Eyewitnesses reveal 'confusion' as masked officers confront 'hazardous material'
Including a shocking story here: Worthing seafront evacuation: 18-month child falls ill after trip to the beach
The investigation is ongoing and we will release more information as soon as we are able to, the spokesman added.
In a tweet at 4.10pm, West Sussex Fire and Rescue Service confirmed it had left the scene and the cordon had been lifted.
See pictures from the scene here: Pictures show Worthing seafront locked down and deserted after ‘hazardous material’ discovered