Unbeaten prospect Danny Gonzalez -- who signed with Mayweather Promotions in 2016 -- was shot and killed on Labor Day, officials confirmed to TMZ.

The 22-year-old was in Moreno Valley, CA on September 7, around 9PM, when someone approached the fighter and opened fire.

The Riverside County Sheriff's Dept. says deputies and paramedics responded to the scene where Gonzalez was pronounced dead.

Two teenagers who were with Gonzalez were transported to a nearby hospital where they were treated for non-life-threatening injuries, officials say.

An investigation is underway, but at the moment no suspects have been identified and cops say they have not determined a motive.

WBC president Mauricio Sulaiman commented on the tragic news Tuesday ... saying, "We are very sad to report the tragic death of boxer and top prospect, Danny González."

"We send our deepest condolences and prayers to the Gonzalez family at this hard time. May Danny rest in eternal peace."

Gonzalez signed with Mayweather Promotions when he was only 18 years old ... and at the time Mayweather raved about the kid.

"There are certain times when you know you've just struck gold and this is one of them," Mayweather said in 2016.

Floyd praised Gonzalez's "incredible amateur record" of 96-13 ... and called him a "force to be reckoned with!"

Gonzalez only had three professional fights before taking time away from the sport in 2017 -- but earlier this year, he posted on social media suggesting a comeback could be in the works.