The Boeing 747 involved in the crash, operated by Turkish freight carrier ACT Airlines on behalf of Emirates, came to rest partially submerged in water after veering off the north runway, the Airport Authority Hong Kong said.
All four crew members on board escaped without injury.
Two airport security officers were pulled from the water unresponsive, one pronounced dead at the scene and the other later in hospital, said Steven Yiu, executive director of airport operations.
The accident, which occurred around 3:50 a.m. local time (1950 GMT Sunday), was Hong Kong’s deadliest airport incident in more than 25 years.
Authorities are investigating possible factors including weather, runway conditions, aircraft performance, and crew actions, Yiu said.
An air traffic control recording reviewed by Reuters indicated the pilot confirmed plans to land on runway 07L but did not report technical issues.
Minutes later, a controller said, “An incident happened at the airfield just now.”
Man Ka-chai, chief accident and safety investigator for Hong Kong’s Air Accident Investigation Authority, said the flight had been cleared to land on the north runway and no distress call was received.
Yiu said the patrol vehicle was operating in its designated area outside the runway fence and “definitely didn’t rush onto the runway.”
The plane suddenly veered left after landing, striking the vehicle in what he called “wasn’t a normal path.”
Flights at Hong Kong International Airport were not affected, he said.
The northern runway will reopen after safety checks, while the south and central runways remain operational.
Photos showed the AirACT-liveried freighter partially submerged near the airport’s sea wall, with its escape slide deployed and its nose and tail sections separated.
The Civil Aviation Department confirmed the aircraft “deviated from the north runway after landing and ditched into the sea.”
Emirates said flight EK9788 sustained damage during landing and carried no cargo.
“Crew are confirmed to be safe,” the airline said in a statement.
Boeing and ACT Airlines did not immediately respond to requests for comment.
FlightRadar24 data showed the 32-year-old aircraft was originally a passenger jet before conversion to a freighter.
Yiu said the airport authority would assist the families of the two victims, who had worked at the airport for seven and 12 years.
The crash was Hong Kong’s deadliest airport accident since a China Airlines flight in 1999 that killed three passengers, according to the Aviation Safety Network.