London

Britain's Prince William has branded racist abuse directed at footballers "despicable" and said it "must stop now" after Manchester United's Marcus Rashford became the latest player to be targeted.

William, who is the president of the Football Association, spoke out on Sunday after the Professional Footballers' Association accused social media companies of lacking the willingness to clamp down on racist posts.

Chelsea defender Reece James, West Brom's Romaine Sawyers and Rashford's team-mates Axel Tuanzebe and Anthony Martial have all suffered online racist abuse over the past week.

Rashford was then targeted after United's 0-0 draw at Arsenal on Saturday, prompting a police investigation.

William tweeted: "Racist abuse -- whether on the pitch, in the stands, or on social media -- is despicable and it must stop now.

"We all have a responsibility to create an environment where such abuse is not tolerated, and those who choose to spread hate and division are held accountable for their actions. That responsibility extends to the platforms where so much of this activity now takes place."

The PFA called on social networks to demonstrate they were truly committed to tackling a problem it says has been "at crisis point" for two years.

"Every effort must be taken to protect them (professional footballers), and all other users, from racist abuse while using social media," it said in a statement.

"Offline consequences for online hate crimes must be pursued whenever possible."

Greater Manchester Police said a number of abusive comments directed at United players had been reported and the force would be "investigating these crimes thoroughly".

Rashford, a high-profile campaigner against child food poverty, said the remarks showed "humanity and social media at its worst,

"I'm a black man and I live every day proud that I am," he tweeted.

"No one, or no one comment, is going to make me feel any different. So sorry if you were looking for a strong reaction, you're just simply not going to get it here."

A 49-year-old man was arrested on suspicion of racially abusing Sawyers.