Four men are due in court in the North later today on charges relating to rioting and the seizure of petrol bombs.
The men, aged between 19 and 22, are due to appear at Craigavon Magristrates Court charged with conspiracy to riot and with possession of materials for petrol bombs.
The arrests follow a number of house searches in the Craigavon area and the arrest of three people in Portadown on Tuesday.
A fourth person was arrested yesterday, the PSNI said.