CLIFTON, N.J. (WABC) -- Four elementary school children from Clifton, New Jersey, are accused of planning to set off an explosive device at a high school.The kids, ages 10 and 11, are fifth-graders from Clifton Elementary School #11.Police said they were allegedly planning to detonate an explosive at an assembly being held at Clifton High School Wednesday.At this point, police haven't said why the kids targeted the high school, but they are treating it as more than a prank.Teachers and administrators at the school reportedly uncovered written plans on how the attack would occur and contacted police.Police found the "device," but there were no explosives inside of it. Instead, it was filled with vinegar and cinnamon, so authorities say while the intent might have been there, the scheme would not have worked.The students were released to their parents. All five have been suspended from school, but there are no official charges at this point.Some parents expressed concern over how they were informed, saying they were the last to know and that the official notification didn't come until Thursday afternoon. And they are not happy about it.A robocall went out, as well as a text message saying that police had questioned students involved and determined there was no danger.