Uber (uber) CEO Travis Kalanick has pledged to launch an “urgent” investigation following a former employee’s allegations of sexual harassment at the company.
Kalanick’s statement, issued Sunday, comes in the wake of accusations published on the personal website of Susan Fowler, a former site reliability engineer (SRE) who quit Uber in December 2016.
In a lengthy post titled “On One Very, Very Strange Year At Uber” Fowler alleges that during her first few weeks at the San Francisco-based tech firm her team manager propositioned her for sex. When she presented the company’s human resources department with screenshots of his inappropriate messages, Fowler says she was told that the company wouldn’t take action beyond talking to the manager because it was his first offense and they didn’t want to ruin the career of a “high performer.”
In two tweets, Kalanick said that what Fowler had described “is abhorrent & against everything we believe in. Anyone who behaves this way or thinks this is OK will be fired.” He added: “I’ve instructed our [chief human resources officer] Liane to conduct an urgent investigation. There can be absolutely no place for this kind of behavior at Uber.”
Fowler, who says other female colleagues reported similar complaints against the same manager, characterizes Uber as an “organization in complete, unrelenting chaos.” She alleges that her performance score declined, and that she was eventually threatened with firing, for reporting her experiences to HR. When she joined the company in November 2015, she writes, 25% of its SRE engineers were women—by the time she left just over a year later this had drastically declined.
Fowler’s allegations have provoked a resurgence of the #DeleteUber hashtag on Twitter. “Everything regarding how Uber handles sexual harassment & gender discrimination – internal & external – is troubling,” wrote one user. Another Twitter user asked Uber “What kind of rape culture are you running over there?”
The #DeleteUber hashtag initially trended after Uber lifted surge pricing around JFK Airport during a strike by the New York Taxi Workers Alliance in December. The taxi drivers were protesting President Trump’s controversial executive order restricting immigration.
For more on past #DeleteUber campaigns, watch Fortune’s video:
Fortune reached out to Uber for comment, but the company said it had nothing to add at this time beyond Kalanick’s statement.