Authorities briefly shut down a security checkpoint at Sky Harbor International Airport and called in the bomb squad Monday morning after a suspicious image appeared on an X-Ray.

The Phoenix Police Department bomb squad ultimately determined that the item wasn't explosive, said Transportation Security Administration Michael England. England wouldn't say what the item was and Phoenix police would only say it was in a carry-on bag.

The checkpoint is one of four at Terminal 4, which serves American and Southwest airlines. American Airlines said about a dozen of its flights were delayed by the roughly hour-long closure, while Southwest flights weren't affected. American Airlines spokeswoman Victoria Lupica said there may be some residual delays but that the airline's operations will gradually return to normal during the day.

Matt Cowan was preparing to board a flight for his trip to Miami when he was evacuated. He says information was sparse during the shutdown and passengers became antsy as they waited to find out what was going on.

"It was infuriating because the TSA refused to tell us anything that was happening," he said.

Once passengers were allowed to go to their gates, Cowan said crews scrambled to make up for the delay.