PHOENIX — More than 3,000 checked bags missed their outbound flights in Phoenix on Thursday because of a problem with a screening system at Sky Harbor International Airport, officials with Transportation Security Administration said.

“TSA is experiencing significant, unprecedented technical issues with its computer server allowing the automated screening of checked bags for explosives,” TSA spokesman Nico Melendez said in a statement.

Melendez didn’t elaborate on the problem, which began about 6:45 a.m. and only affected Sky Harbor.

There was no immediate timetable for the problem to be fixed. But Melendez said TSA hoped to be back online shortly and that it wasn’t a safety issue.

“TSA is working diligently with our airline and airport partners and using alternative screening tools to screen bags, though that method are not as efficient as our automated system,” Melendez added. “TSA is currently bringing additional canine units from other airports and bringing in network specialists to address the situation and keep passengers safe and screen all bags.”

According to the TSA, the inline baggage systems handle the bulk of checked luggage. When everything is working properly only about 10 per cent of all checked bags are hand-searched by TSA officers.

Julie Rodriguez, a Sky Harbor spokeswoman, said the problem existed in all three of the airport’s terminals and passengers were being advised to avoid checking luggage if possible.

Video and photos from the airport late Thursday afternoon showed hundreds of bags sitting in a parking lot that is usually used for special events.

Rodriguez said those bags were slated for ground transportation to airports in Tucson and San Diego and then would be screened and flown on to their destinations.

“We are not seeing widespread flight delays, but many checked bags are missing flights,” Rodriguez said.

Sixteen airlines fly in and out of Sky Harbor, which is one of the nation’s busiest airports. Nearly 4.3 million passengers travelled through Sky Harbor in March, making it the airport’s busiest month ever.