Uber chief executive Travis Kalanick has announced an "urgent investigation" at the ride-sharing company after a former employee wrote a blog post Sunday alleging sexual harassment and sexism at the firm.
"What's described here is abhorrent (and) against everything we believe in. Anyone who behaves this way or thinks this is OK will be fired," Kalanick said on Twitter.
"I've instructed our (Chief Human Resources Officer) Liane Hornsey to conduct an urgent investigation. There can be absolutely no place for this kind of behavior at Uber."
Susan Fowler, an engineer who worked at Uber until the end of last year, said her manager made sexual advances shortly after she joined the company at the end of 2015.
She said she complained to more senior managers and the company's human resources department, but was told that it was the man's "first offense" and that they wouldn't feel comfortable punishing a "high performer."
Fowler said she was given the choice of joining another team, or staying in her position with the possibility of receiving a poor performance review from her manager.
Other the next few months, Fowler said she met other women engineers at the company who said they had also experienced similar harassment, including alleged inappropriate behavior from her previous manager.
After lodging various complaints of what she considered inappropriate behavior, Fowler said she was told by her manager that she was "on thin ice" for reporting his boss to human resources.
The HR department, meanwhile, told her that she might be the problem, not the men she was reporting.
Fowler said she was blocked for a transfer and given a negative performance review without justification.
She now works at Stripe, a company that helps businesses handle online and mobile payments.
The Uber case is likely to revive debates over sexism in male-dominated Silicon Valley.
In 2015, a California jury rejected charges of gender discrimination against a prominent venture capital firm in a case seen as a proxy trial of Silicon Valley sex bias.
Ellen Pao had sued Kleiner Perkins Caufield and Byers (KPCB), saying she was fired after complaining about bias at the firm that notably backed Amazon, Facebook and Google.