The RUC is searching premises in Ballymena in Co Antrim today following recent sectarian pipe-bomb attacks in the area, a spokesman said.
A man whose house was damaged in the latest attack in the neighbouring town of Larne warned the attacks would end in death if more was not done to tackle the problem.
"It's a daily occurrence. This is happening throughout the town week in week out," he said. "Eventually somebody's going to get killed."
RUC commander for the Larne area Supt Karen Kennedy called it a "cowardly and reckless attack".
"Again serious injury or loss of life could have occurred," she said.
She said the RUC in Larne remained dedicated to preventing the attacks and making arrests. "I would urge anyone in the community who has any information about the identity of the criminals carrying out these evil acts to contact police as soon as possible," the superintendent added.
PA