vacated AA flight to Mexico
© Reuters / Lucas JacksonAn American Airlines airplane at Miami International airport in Miami, Florida
A "security concern" caused the evacuation of all passengers from an American Airlines flight heading to Mexico City at Miami International Airport. The threat has since been lifted without an official explanation.

Miami-Dade Police Department confirmed it investigated a security concern at the airport. Passengers disembarked and necessary "safety protocols [were] set in place," police said in a tweet.

K-9 units were dispatched to the aircraft, according to eyewitnesses.

American Airlines dismissed the concern as a "non-credible threat, that should be cleared momentarily," according to Reuters.

Still, officers in full protective gear armed with assault rifles were spotted at the scene.

Juha Mikkola, a passenger on the evacuated flight, tweeted that people were kept in the dark about the cause of the flight's delay and the extensive checks to which they were being subjected. He said that law enforcers were searching the passengers' phones.

Less than an hour after the initial alert, police gave the all-clear for passengers to board the plane and depart for Mexico City.