The security breach at Denver International Airport Thursday was triggered by federal agents pursuing two suspects.

Two Immigration and Customs Enforcement agents and a Secret Service agent dressed in plain clothes went through the passenger screening area without being verified by screeners. The Transportation Security Administration closed down screening stations and stopped the airport's trains for about 20 minutes while federal air marshals and police searched for the agents.

They were found on Concourse B and had arrested the suspects, who were suspected of trafficking in counterfeit goods.

TSA spokeswoman Carrie Harmon said officials met with the agencies involved to review what happened.