Denver International Airport temporarily evacuated a section of its main terminal on Tuesday afternoon, as officials investigated a possible security threat, Reuters reported.
The evacuation area included the west side of the main terminal levels 5 and 6. Flights continued while the possible threat was investigated.
The airport tweeted that the threat was in the form of a suspicious package in the main terminal, but later said that no threat was found.
The incident comes amid a heightened security alert at major U.S. airports, following attacks in Brussels earlier in the day.
One of the attacks in Brussels targeted the Zaventem airport, which was rocked by at least two explosions which killed at least 14 people and wounded 90 others.
A ceiling in the airport collapsed in the wake of the explosion, trapping dozens of travelers and complicating efforts to recover victims of the attack.
Another explosion just an hour targeted the Maalbeek metro station in the Belgian capital.
The Islamic State (ISIS) group claimed responsibility.