Triple world track cycling champion Kelly Catlin has died at the age of just 23, it has been announced.
The American, also an Olympic silver medallist, tragically passed away in California.
There are no suspicious circumstances.
"The US cycling community suffered a devastating loss with the passing of Kelly Catlin, USA Cycling national team member," said USA Cycling President and chief executive Rob DeMartini.
"Kelly was more than an athlete to us, and she will always be part of the USA Cycling family.
"Our thoughts and prayers are with the Catlin family.
"This is an incredibly difficult time and we want to respect their privacy.
"The entire cycling community is mourning this immense loss.
"We are offering continuous support to Kelly's team-mates, coaches and staff."
DeMartini added: "We also encourage all those who knew Kelly to support each other through the grieving.
"We are deeply saddened by Kelly's passing, and we will all miss her dearly.
"We hope everyone seeks the support they need through the hard days ahead, and please keep the Catlin family in your thoughts."
Catlin won consecutive track world titles in the team pursuit in 2016, 2017 and 2018.
She won Olympic silver in the same event at Rio 2016.
In 2017 and 2018, Catlin also won world bronze medals in the individual pursuit.
"There isn't a minute that goes by that we don't think of her and think of the wonderful life she could have lived," her father Mark Catlin wrote in a letter to VeloNews.
"There isn't a second in which we wouldn't freely give our lives in exchange for hers.
"The hurt is unbelievable."