The PSNI has uncovered what it describes as a bomb factory and has made a substantial find of weapons which they say is linked to the feud within the UDA.
The discovery followed a 13-hour security operation at the loyalist Castlemara housing estate in Carrickfergus, Co Antrim. Six people from the area were being questioned last night.
Bomb-making equipment, explosives, pipe bombs, an under- car booby-trap device, a handgun and ammunition and component parts of four explosive devices were found during a search in the estate yesterday.
British army technical experts worked yesterday to make the haul safe after being called to the scene on Thursday night following the initial discovery of a suspicious object.
About 15 homes were evacuated during the search, police said.
The discovery was made during follow-up searches after a shooting incident in Dunluskin Gardens in the same area on Tuesday night in which Mr Robert Ewart (37) was shot and critically injured.
That incident is also linked to the UDA feud.
Acting Assistant Chief Constable for greater Belfast, Mrs Maggie Hunter, said: "We are delighted to remove this material from our streets which undoubtedly would have resulted in death, serious injury and destruction.
"As a result of the find we have made three arrests. Three other people remain in police custody in connection with Tuesday's shooting."
Mrs Hunter linked the weapons find to the ongoing loyalist feud which began last autumn.
She said 12 people have been charged with various offences in connection with the feud and 22 house searches have been carried out.
"We have seen this feud spread around parts of Belfast, Co Down, Newtownabbey and now Carrickfergus . It is time for this feuding to stop before more lives are lost.
"We have a team of 70 investigators working on this feud investigation with additional support from uniformed officers.
"We need more successes like the find in Castlemara. However, this can only be achieved with the help and support of local communities," she said.