Los Angeles Lakers great Kobe Bryant, 41, and his 13-year-old daughter Gianna have died in a helicopter crash, NBA commissioner Adam Silver confirmed.

American news outlet TMZ reported that Bryant and his daughter died in a crash in Calabasas, a city in California, around 10am local time on Sunday. 

Speaking at a news conference, Los Angeles County sheriff Alex Villanueva announced nine people were on board, though he did not confirm their identities.

Silver said: "The NBA family is devastated by the tragic passing of Kobe Bryant and his daughter Gianna.

"For 20 seasons, Kobe showed us what is possible when remarkable talent blends with an absolute devotion to winning. He was one of the most extraordinary players in the history of our game with accomplishments that are legendary: five NBA championships, an NBA MVP award, 18 NBA All-Star selections, and two Olympic gold medals.

"But he will be remembered most for inspiring people around the world to pick up a basketball and compete to the very best of their ability.

"He was generous with the wisdom he acquired and saw it as his mission to share it with future generations of players, taking special delight in passing down his love of the game to Gianna.

"We send our heartfelt condolences to his wife, Vanessa, and their family, the Lakers organisation and the entire sports world."

TMZ said eyewitness told how they heard the helicopter's engine stuttering before it went down and a fire broke out, with emergency services responding.

Villanueva provided an update to the media at a news conference alongside Los Angeles County Fire Department chief Daryl Osby but said it would be "inappropriate" to name the deceased.

"Personnel responded to the scene of the fire, assisted fire department, established containment area," said Villanueva.

"The FAA [Federal Aviation Administration] is already on scene and assisting. We're awaiting the arrival of the coroner's office to assist with the recovery of the remains. As the chief [Osby] indicated there were no survivors. We have a manifest copy which indicates there were nine people onboard the aircraft – the pilot plus eight individuals. 

"There is wide speculation as to who the people are but it would be highly inappropriate right now to identify anyone by name until the coroner has made identification through their deliberate process and made notifications to the next of kin.

"It would be extremely disrespectful to learn your loved one has perished through TMZ, that is just wholly inappropriate so we will not be going there. We'll wait until the coroner does her job.

"We are assisting the families of those we believe who have been impacted. It's a tough process. Our hope goes out to all of the families of everyone on board and God bless their souls.

"At this point there is nothing we can add until the coroner does her job. When we have the information and know the rest of kin have been notified, then we can release the information publicly. [The media] will be notified in subsequent announcements."

Asked if there were nine bodies at the scene, Villanueva replied: "That is our belief, yes."

Bryant spent his entire 20-year career from 1996 until 2006 with the Lakers.

He was selected with the 13th overall pick by the Charlotte Hornets in the 1996 draft before being traded to the Lakers.

The Los Angeles franchise famously retired both of Bryant's jerseys – the numbers eight and 24 – making him the only player in the team's history to receive that honour.