SAN FRANCISCO (BLOOMBERG) - Uber Technologies chief executive officer Travis Kalanick is struggling to hold onto his top lieutenants as the company faces an onslaught of scandals.

Rachel Whetstone, who led policy and communications under Kalanick, resigned on Tuesday (April 11) after almost two years at Uber. She supervised the company's expansive lobbying efforts, helping to strategize its battles with governments around the world. She was also in charge of Uber's public relations team, which has grappled with a series of crises this year.

"I am incredibly proud of the team that we've built," Whetstone said in a statement. "I joined Uber because I love the product-and that love is as strong today as it was when I booked my very first ride six years ago."

The backlash against Uber this year started after Kalanick joined President Donald Trump's business advisory board. The move helped jumpstart the hashtag #DeleteUber, which drove hundreds of thousands of people to get rid of the app. The company has faced crisis after crisis, including a video published by Bloomberg that shows Kalanick arguing brashly with an Uber driver.

Several of Kalanick's direct reports either resigned or were asked to leave this year. In February, the CEO dismissed Amit Singhal, the new head of software development, after the company learned of a sexual harassment claim from a previous job. Singhal denied the allegation. Ed Baker, the vice president of product and growth, left a few days later. Jeff Jones, the president of ridesharing and Kalanick's designated No 2, quit a couple weeks after that.

Whetstone was hired to replace David Plouffe, the former campaign manager for President Barack Obama. She soon brought on Jill Hazelbaker, who worked with her at Google. Hazelbaker will now take over for Whetstone.