UPDATED 6:45 p.m. ET
Normal operations have resumed at Hartsfield-Jackson Atlanta International Airport after investigators did not find bombs on two commercial aircrafts that were forced to land Saturday following "credible" threats.
"The all clear has been given and no devices were discovered on board either aircraft," Reese McCranie, the airport's director of communications confirmed to Mashable.
Portions of the world's busiest airport were shut down earlier due to the bomb scare.
Investigators had searched the two planes, belonging to Delta and Southwest Airlines (flight 1156 and flight 2492, respectively), an FBI spokesman told The New York Times.
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"We believe the threats to be credible," McCrainie told The Atlanta Journal Constitution earlier in the day.
Military fighter jets escorted the flights to the airport, the planes landed safely and the runway was now closed.
"Due a security situation, upon safely landing as scheduled in Atlanta, the aircraft operating Flight 2492 from Milwaukee taxied under its own power to a remote area of the airport where 86 Customers and the aircraft are being rescreened," a Southwest Airlines spokesperson told Mashable in a statement, declining to comment further. "Our top priority is the Safety of our Customers and Employees. We cannot comment on the nature of the security situation."
It's believed that the threats were made via Twitter by a user only identified as "Zortic."
"I have a bomb on one of your planes, but I forgot which one when I left the airport. Can you help me find it?" reads Zortic's tweet at the official Delta assistance Twitter account. The flight number referenced in the thread matches the number of the Delta plane that landed in Atlanta.
The account made similar threats to Southwest Airlines through tweets.
“A bomb was placed on SWA2492," reads a Zortic tweet directed at Southwest Airlines. "It will be detonated at a random time of my choosing,” and “If anything happens to me I’ll make sure that more flights are targeted. I strongly suggest you don’t try anything stupid.”
The only thing that will happen is my Twitter getting suspended. I'm untouchable always have been.— Zortic (@kingZortic) January 24, 2015
Delta did not immediately respond to a request for comment.