Police are appealing for calm after three nights of violence at a Berkshire dairy owned by a Muslim family.
Mounted police have been patrolling outside the dairy after the attacks
The Medina Dairy in Windsor was hit by a suspected petrol bomb on Wednesday evening, on the third night of unrest.
Police have stepped up patrols in the Dedworth area and said they would use "robust policing tactics" to bring the situation under control.
Three people were arrested on Tuesday and one was later charged with being in possession of an offensive weapon.
Police have said another two petrol bombs were found near the dairy.
Ch Supt Brian Langston said: "This disorder appears to have escalated from a minor disagreement.
"As a result, we have seen groups of Asian and white local youths gathering in the area of Vale Road.
"The type of behaviour shown over the past few evenings will not be tolerated by police, and we will not allow any section of the community to be intimidated by mindless violence.
"Three arrests have already been made and we will continue to use robust policing tactics to deal with anyone threatening public safety."
Detectives said a bottle "containing accelerant" was thrown at the front of a building at the dairy on Wednesday night, but did not ignite.
The disorder started on Monday evening following what is believed to have been a minor verbal dispute between a group of youths and another person.
The former Express dairy site now has Muslim owners who run a 24-hour operation and have proposed plans for an Islamic religious centre on the site.
On Tuesday night, large groups of people gathered in the area and police arrested two 16-year-old boys and a 23-year-old man.
One of the 16-year-olds was later charged.