A United States’ transport safety agency is deploying five investigators to Hong Kong to assist with the city’s probe into the cargo plane crash that killed two security workers, while the four aircrew involved have met with local authorities.

The National Transportation Safety Board (NTSB), an independent US government agency responsible for investigating civil transport accidents, said on social media that it would send its team to Hong Kong to assist with the probe into the plane crash.

“The NTSB is sending a team of five investigators to Hong Kong to assist the [city’s] Air Accident Investigation Authority (AAIA) investigation into Monday’s runway excursion at Hong Kong International Airport involving a Boeing 747-418 owned by Turkish cargo airline ACT Airlines,” it said on Wednesday Hong Kong time.

The US agency is responsible for determining the probable cause of civil transport accidents and formulating safety recommendations to prevent future occurrences.

The agency’s response follows Emirates Flight 9788 from Dubai, operated by Turkish cargo charter carrier ACT Airlines, which veered off the runway during landing around 3.50am on Monday. The aircraft crashed into the sea off the north runway, resulting in the deaths of two workers in a security vehicle. AAIA is conducting the investigation.

A source familiar with the matter told the Post on Wednesday that the four crew members on board the plane had already met with AAIA and were expected to be questioned by police.

The crew were captain Atilia-silifke Yilmaz, 35; first officer Candemir Ulker, 44; aircraft maintenance engineer Muzaffer Tuydu, 46; and loadmaster Caner Durgut, 35.