NEW YORK – Tennis star Serena Williams has become the latest athlete to speak out about racial tensions in United States following the deaths of black men at the hands of police.

In a Facebook post, the 22-time Grand Slam winner vowed not to be silent on social injustice in the wake of protests against the slayings around the country.

Williams joined the debate on police violence after admitting she was scared at the sight of a police officer while her 18-year-old nephew was driving her to meetings.

Williams’ post said the sight of a police officer while her nephew was at the wheel made her ‘regret’ not driving herself – referencing the death of Philando Castile, 32, who was shot dead by a Minnesota police officer in July.

The US has seen a spike in racial tensions in the past week following the killings of Terence Crutcher, 40, in Tulsa, Keith Lamont Scott in Charlotte and Alfred Olango, 30, in California.

Mr Olango was the 217th black person killed by police in the US this year, according to the Mail Online.

The US law enforcement officers killed up to 1,199 people last year, the majority of whom were ‘people of color’.

About 14.3% of Americans or 45,672,250 people are Black only or Black in combination with another race as of 2014 estimates.

Also known as Black Americans, the Black or African-American group is the largest racial minority, as opposed to Hispanics and Latinos, who are the largest ethnic minority.