The Transportation Security Administration is experiencing some of the highest wait times in its history — with some airline passengers waiting more than 4.5 hours to make it through security checkpoints, a top official told Congress Wednesday.

TSA acting administrator Ha Nguyen McNeill testified to the House Homeland Security Committee that her beleaguered agency is “being forced to consolidate … and may have to close smaller airports if we do not have enough officers.”

“It is a fluid, challenging and unpredictable situation. We understand this is frustrating and disruptive,” she added.

“This is unacceptable and we will not be tolerated.”

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