The PSNI has said it is working hard to avoid reprisal attacks following the murder of a high-profile loyalist in Carrickfergus.
George Gilmore, 44, died after he was shot while in his car in the town on Monday afternoon.
A dispute between loyalist factions in the town has been ongoing for months.
Det Ch Supt Raymond Murray said the "landscape and environment" in Northern Ireland meant retaliation was a possibility.
Police have described the murder as a "ruthless attack in broad daylight" and appealed for help in indentifying those involved.
One of the bullets fired during the attack could have hit someone else, police said.
"At least one of the bullets that was fired at the victim missed and went through the front door of the house and could well have hit an occupant," said Det Ch Supt Murray on Tuesday.
He also said a link to the south-east Antrim element of the Ulster Defence Association (UDA) paramilitary group was a very strong line of inquiry.
He rejected any suggestion the police had lost control of paramilitary feuds in the County Antrim town, but added: "We need people to come forward and give us evidence."
Det Ch Supt Murray said police believe there were probably two gunmen involved in Monday's attack.
He said they may have come from an alleyway near Pinewood Avenue in Carrickfergus to carry out the attack, may have made off on foot and may have been wearing dark clothing.
Det Ch Supt Murray said police had spoken to a number of witnesses.
"What we have to do now is collate those accounts and come to a balanced opinion about what has taken place," he said.
"Those involved had no consideration for the local community when they carried out their attack in a residential street populated with families, young children and older people."
Earlier, Democratic Unionist Party MP Sammy Wilson said the feud involved two factions of the UDA.
"One side, in broad daylight and unmasked, have taken the opportunity to try to kill one of the Gilmore family," he added.
Ulster Unionist MLA Roy Beggs urged the factions involved in the feud to remain calm in the wake of the attack.
"Let this be a learning point - stop the paramilitarism, bring it to an end, because it is ruining our communities," said the East Antrim representative.
"I am fearful that others may wish to start a tit-for-tat war, but if that happens everybody loses."
The UDA's motto is Quis Separabit (Who shall come between us).
Writing in the Belfast Telegraph, veteran reporter Jim McDowell says: "Now, once again, they only have to look in the mirror to find the answer."
The shooting came after a serious assault on a doorman at a nearby bar on Sunday.