Denver (AP) Denver International Airport officials say a security breach prompted a brief shutdown of passenger-screening checkpoints and trains between the main concourse and boarding gates.

The nature of the Thursday morning breach has not been disclosed.

The screening checkpoints and trains were operating again by 10:30 a.m. after a shutdown of a little over 20 minutes.

An average of more han 148,000 passengers a day used the airport in March, the most recent month for which totals have been reported.