Time's Up president Lisa Borders stepped down after allegations of sexual assault were made against her son, the group has announced.

Borders revealed she was leaving the anti-sexual harassment movement on Monday, four months after taking the job of president and chief executive officer.

The former Coca-Cola executive said she needed to "address family concerns".

Now, Time's Up has said she left following allegations against her son.

In a statement, the group said: "Time's Up unequivocally supports all survivors of sexual harassment and abuse.

"On Friday, Lisa Borders informed members of Time's Up leadership that sexual assault allegations had been made against her son in a private forum.

"Within 24 hours, Lisa made the decision to resign as president and CEO of Time's Up and we agreed that it was the right decision for all parties involved.

"All our actions were fully guided by our support for survivors."

Borders is a former executive at Coca-Cola and the Women's National Basketball League.

She was unveiled as Time's Up's first president in October.

Time's Up was started in the wake of the Harvey Weinstein scandal and aims to improve workplace conditions for women and stop sexual harassment.

Prominent members include actress Emma Watson.