NBA star LeBron James was facing a firestorm of criticism from the US rightwing Friday over an incendiary tweet targeting an Ohio police officer who fatally shot a Black teenager, with conservative pundits accusing the athlete of racism and irresponsible behavior.

The policeman shot dead 16-year-old Ma'Khia Bryant as she lunged with a knife at another girl in James's home state of Ohio -- prompting the Lakers star to post a picture of the officer on Twitter with the words "YOU'RE NEXT #ACCOUNTABILITY."

The killing coincided with the guilty verdict aginst the white police officer charged with the murder of George Floyd, a Black man whose death in Minneapolis last year sparked nationwide protests.

The 36-year-old NBA star, popularly known as "King James," took down the tweet hours later, explaining his post was "being used to create more hate -This isn't about one officer. it's about the entire system and they always use our words to create more racism. I am so desperate for more ACCOUNTABILITY."

That explanation did little to stem the tide of anger on social media, stoked by prominent rightwing pundits led by former president Donald Trump who said "His RACIST rants are divisive, nasty, insulting, and demeaning. He may be a great basketball player, but he is doing nothing to bring our Country together!"

Tom Cotton, a hardline Republican senator from Arkansas, took to Twitter to say that "Lebron James is inciting violence against an Ohio police officer. This is disgraceful and dangerous. Is the NBA okay with this? Is Twitter?"

James had avoided wading into social issues in the early days of his sporting career, but that changed with the shooting of Trayvon Martin, an unarmed Black teenager shot dead in 2012 by a man who subsequently avoided jail under Florida's "Stand your ground" law.

"I think it starts with the Trayvon Martin situation and the reason it starts with that, I believe is because having kids of my own — having boys of my own — it hit home for me to see and to learn the story and to think that if my boy left home and he never returned," he said in an interview with CNN in 2018.

Since then he has often spoken out about racial discrimination in the country.

"I think it's just the natural evolution and growth of a man," his longtime friend Maverick Carter told the sports new website Bleacher Report in 2018.

'Shut up and dribble'

Thanks to his status as an athlete, his commentary on social issues and his activism, James is now seen as one of the most influential sports personalities in the political sphere.

He had several very public spats with Trump in the past, most frequently played out on Twitter before the social media platform barred the former president over his own incitement of a mob that attacked the US Capitol on January 6.

James even produced his own 2018 documentary series on the political engagement of Black athletes called "Shut Up and Dribble," whose title was drawn from a Fox News commentator's reaction to the basketball player's clashes with Trump.

He also has a television talk show on HBO with Carter, who is a businessman, called "The Shop" in which he discusses social issues of the day with prominent personalities.

In 2020, the four-time NBA player of the year went even further by launching "More Than a Vote", recruiting tens of thousands of volunteers to encourage Black people to register to vote ahead of last year's elections, in which Trump was defeated by Democrat Joe Biden.

"LeBron James should focus on basketball rather than presiding over the destruction of the NBA, which has just recorded the lowest television RATINGS, by far, in the long and distinguished history of the League," Trump said in his statement.

In 2016, Trump linked bad ratings at the NFL to the movement started by quarterback Colin Kaepernick, who had taken a knee during the national anthem at ball games in protest of police violence against Black people.

The WNBA women's basketball league racked up the highest ratings gains among major US leagues in 2020 when its players were by far the most active in supporting the movement that emerged after George Floyd's death.

After his tweet on Wednesday, several conservative figures recalled that in October 2019 LeBron James had criticized a tweet by an NBA executive who publicly supported pro-democracy protesters in Hong Kong.

At the time, LeBron was accused of putting his own financial interests in China ahead of the struggle for democracy and human rights.