The Transportation Security Administration says more than 3,000 bags checked bags missed their outbound flights in Phoenix because of a problem with a screening system.

TSA spokesman Nico Melendez says the technical issue began about 6:45 a.m. Thursday at Phoenix Sky Harbor International Airport.

There's no estimate on when the problem will be fixed.

Sky Harbor officials say they're advising passengers to avoid checking luggage if possible.

Melendez says TSA is working with its airline and airport partners and using alternative screening tools to screen bags, though those methods aren't as efficient as their automated system.

Melendez also says TSA is bringing additional canine units from other airports and bringing in network specialists to address the situation and screen all bags.