LeBron James sent his support to NASCAR's Bubba Wallace after someone hung a noose in his garage area Sunday at Talladega.

"Sickening! Bubba Wallace my brother! Know you don't stand alone! I'm right here with you as well as every other athlete," James tweeted. "I just want to continue to say how proud I am of you for continuing to take a stand for change here in America and sports! NASCAR I salute you as well!"

NASCAR announced late Sunday night the sport is launching an "immediate investigation" into the matter. ESPN's Marty Smith reported Wallace, NASCAR's only full-time black driver, never saw the noose and was alerted to it after a crew member had notified racing officials.

Wallace, who has been an outspoken proponent of the Black Lives Matter movement and led the push in NASCAR's Confederate flag ban, said he was "incredibly saddened" in a statement:

"Today's despicable act of racism and hatred leaves me incredibly saddened and serves as a painful reminder of how much further we have to go as a society and how persistent we must be in the fight against racism. Over the last several weeks, I have been overwhelmed by the support from people across the NASCAR industry, including other drivers and team members in the garage. Together, our sport has made a commitment to driving real change and championing a community that is accepting and welcoming of everyone.

"Nothing is more important, and we will not be deterred by the reprehensible actions of those who seek to spread hate. As my mother told me today, 'They are just trying to scare you.' This will not break me. I will not give in, nor will I back down. I will continue to proudly stand for what I believe in."

Several supporters of the Confederate flag showed up outside Talladega facilities with the flag waving, and a flag flew above the track that read, "Defund NASCAR."

Because the noose hung in the garage area, it has led to speculation that the person who hung it was likely someone within the sport and not a fan who had gained unauthorized access to the area.

Rachel Nichols of ESPN and Jenna Fryer of the Associated Press tweeted:

NASCAR was slated to host 5,000 fans to Sunday's race, which was postponed to Monday because of rain.