US authorities say the person found dead inside a Tesla Cybertruck that exploded in Las Vegas on New Year's Day is believed to be an active member of the US military.

Seven people were injured in the blast and fire outside the entrance of Trump International Hotel.

Investigative authorities said on Thursday that a passport and other items found inside the Cybertruck indicate that the person is a 37-year-old US Army special operations soldier from Colorado.

The authorities said they also found fireworks, camp fuel canisters and two firearms in the wrecked vehicle. They believe the man shot himself in the head before the vehicle exploded.

While the motive remains unclear, the authorities are not ruling out terrorism. They plan to interview the man's acquaintances and analyze data from his computer.

President Joe Biden said on Thursday that investigators are looking into a possible link between this incident and a deadly vehicle attack in New Orleans. Both took place on New Year's Day.

Biden said investigators have not found any evidence of a connection so far, but that he has directed them to accelerate their probe.