US police who searched two planes in Atlanta found no bombs after online threats were made against the aircraft.

FBI spokesman Stephen Emmett said law enforcement officials finished their search on Saturday night at Hartsfield-Jackson Atlanta International Airport.

The threats targeted Southwest Airlines Flight 2492, which arrived from Milwaukee, and Delta Air Lines Flight 1156, which arrived from Portland, Oregon.

Both flights arrived safely.

NORAD spokesman Preston Schlachter said the threats were made through Twitter.

The military dispatched two F-16 fighter jets to shadow the planes until they reached the airport.

AFP/Reuters