Denver International Airport passengers are still facing long security checkpoint lines Tuesday, causing some to miss flights and leaving many complaining in frustration.

“We continue to be very busy,” the airport said in a tweet. “Please allow plenty of extra time at the airport for security screening. At least two hours prior to flight.”

Transportation Security Administration checkpoint wait times were over 90 minutes long on Monday night and into Tuesday morning.

DIA estimates that Sunday was its seventh-busiest day ever, with 175,000 passengers.

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Read more at denverpost.com.