LAS VEGAS (AP) — On Friday, a Southwest Airlines plane bound for Las Vegas from Southern California experienced a sudden drop shortly after takeoff, prompted by an alert regarding a nearby aircraft. This incident resulted in injuries to two flight attendants, according to officials and passengers.

Flight 1496 of Southwest Airlines was responding to an onboard notification about another plane in its vicinity, as reported by the Federal Aviation Administration (FAA). An investigation by the FAA is underway.

According to a statement from the airline, the crew reacted to two air alerts which necessitated the pilot to first ascend and then descend. The flight had departed from Hollywood Burbank Airport shortly before noon.

Passengers posted on social media that the plane took a dramatic drop soon after takeoff.

“Pilot said his collision warning went off & he needed to avoid plane coming at us,” comedian Jimmy Dore posted on X.

The plane was not in the immediate vicinity of the Hollywood Burbank Airport, north of Los Angeles, at the time, said Mike Christensen, an airport spokesman. Christensen said that neither the control tower or the operations department, which tracks planes departing and arriving, have any record of the Southwest flight plunging in their airspace.

Southwest said the flight continued to Las Vegas, “where it landed uneventfully.” The airline said that it is working with the Federal Aviation Administration “to further understand the circumstances” of the event.

This close call is just the latest incident to raise questions about aviation safety in the wake of January’s midair collision over Washington, D.C., that killed 67 people.