A Connecticut school district is banning clown costumes and any "symbols of terror" during this year's Halloween season as authorities investigate the authenticity of a number of clown-related social media posts.

New Haven Public School officials said principals and building leaders have been requested to ban the costumes until additional information is available.

This comes amid an investigation involving police into an account on the photo-sharing social media site Instagram. The account uploaded four photos showing menacing-looking clowns with captions telling several area schools to "watch out" and "wait and see" whether the alleged threats are fake.

Garth Harries, New Haven's school superintendent, said Tuesday the posts have been disruptive to learning and to the school's sense of security.

"There is no question that whoever is promulgating this is making threats," said Harries. "We don't believe there is any credible threat of violence, but they are still making people uncomfortable."

New Haven police said any threat deemed credible could be prosecuted under a new state law that makes a tangible threat against a school a felony. Officer David Hartman, a police department spokesman, said the Instagram posts do not meet that threshold.

"We're not going to shut schools down for this stuff," he said.

Harries said there was a minor incident at a middle school, where an administrator confiscated a clown mask from a group of students who he said were "horsing around."