A noose was left in the garage of coloured NASCAR driver Bubba Wallace at the Talladega Superspeedway in Alabama.
Wallace is the only black driver in NASCAR, and officials have made clear that those behind the act of racism and will be 'eliminated' from the sport.
"Late this afternoon, NASCAR was made aware that a noose was found in the garage stall of the 43 team. We are angry and outraged, and cannot state strongly enough how seriously we take this heinous act," said NASCAR officials in a statement.
"We have launched an immediate investigation, and will do everything we can to identify the person(s) responsible and eliminate them from the sport.
"As we have stated unequivocally, there is no place for racism in NASCAR, and this act only strengthens our resolve to make the sport open and welcoming to all."
Wallace had already successfully campaigned to have the Confederate flag, common white supremacist symbol, banned from being on display at NASCAR events.
However, the flag also represented the southern states, including Alabama, during the American Civil War, and the decision caused a spike in tensions.
Reacting to Sunday's events, Wallace said these events have only strengthened his resolve to create change.
"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," wrote Watson.
"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."
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