Four more arrests have been made after anti-immigration disorder in Norfolk, including a teenager being held on suspicion of assaulting an emergency worker.

Tensions flared in Thetford last week when homes linked to asylum seekers were targeted and police officers were assaulted during three nights of unrest.

Norfolk Police said officers were “subjected to significant aggression” in Thetford on Wednesday, including officers being hit with a rock, bitten and spat at.

The force said on Tuesday that a teenage boy was arrested on suspicion of assaulting an emergency worker on Wednesday, 5 August. He remains in custody.

A man in his 40s was arrested and bailed on suspicion of a public order offence, inciting racial hatred and obstructing a highway on 4 August.

A man in his 30s was arrested and bailed on suspicion of obstructing a highway on 4 August.

A man in his 20s was arrested and bailed on suspicion of a public order offence on 5 August.

Police said another man, who was previously arrested on Sunday, appeared in court on Tuesday and pleaded guilty to drugs offences.

Rodrigo Ramos, 26, of St Johns Way, Thetford, pleaded guilty at Norwich Magistrates’ Court to possession of cocaine with intent to supply and possession of cannabis, the force said.

Officers said Ramos was remanded in custody and is due to be sentenced at Norwich Crown Court on 14 September.