This is a developing story. Please check back for updates.

Albuquerque International Sunport was locked down Friday amid a security concern near the Transportation Security Administration (TSA) checkpoint. No one was allowed past the third floor of the airport, KOAT-TV reported.

"They are not allowing anybody up to the third level," Sunport spokeswoman Stephanie Kitts told the Albuquerque Journal.

It remained unclear what the exact reason for the lockdown was, though one passenger told KOAT there was a suspicious bag.

Travelers took to Twitter to voice their frustrations and tell of their experiences in the airport Friday. 

“Just landed in ABQ,” one person wrote. “Airport on lockdown apparently. We are stuck at the gate.”

Others said there was no one coming in and no one coming out. 

“Airport security shutdown at #ABQ has me and friends stuck at Gate A11,” another person wrote. “Willing to battle anyone at thumb wars while we wait.”

It remained unclear what the impact on flights in and out of the facility was.​ The airport said on its official Twitter account that it would provide updates as time went on.