Content Warning: The following article discusses a fatal shooting incident. Reader discretion is advised due to the sensitive nature of the content.

The chief executive of one of the United States's largest health insurance companies, UnitedHealthcare, was shot and killed outside a New York Hilton hotel in an apparently targeted hit Wednesday, US media reported.

The New York Times reported that Brian Thompson, 50, was shot just before 7 a.m. at the hotel in the Midtown district of Manhattan, with the CNBC broadcaster suggesting a silencer had been used in the attack.

The gunman, described as wearing a black face mask, then fled following the incident, which is expected to spark a manhunt.

Police confirmed a shooting at the location with officers swarming around the area around the hotel, a usually busy corner of Manhattan that would have been filled with commuters at the time of the shooting.

UnitedHealth Group, the parent company of UHC, had revenues of $100.8 billion in the third quarter of the year.

UnitedHealthcare's Employer and Individual products are used by almost 30 million people in the United States according to an investor presentation.

The company was due to hold an investor day in New York Wednesday at which Thompson was scheduled to deliver a keynote speech.

The event has subsequently been canceled, CNBC reported.