The CBC, a group composed of black lawmakers in the U.S. Congress, is urging the embattled ride-hailing company to consider appointing executives of color to its highest levels of leadership, according to Recode.

“Uber has a unique opportunity to elevate their stated commitment to diversity by hiring a person of color for a C-suite level position, and appointing a board member of color,” Rep. Barbara Lee (D-Calif.) told Recode.

This comes at a time when Uber has multiple vacancies at the highest levels, including the chief executive officer, chief operating officer, chief financial officer, chief marketing officer, and general counsel positions.

Although Uber recently hired female executive Bozoma Saint John away from Apple to serve as its chief brand officer, it still has work to do.

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In March, Uber released its diversity numbers for the first time, following a barrage of criticism for keeping them private. Women in leadership accounted for 22% of Uber’s employee base. For tech and engineering roles, that number dropped to 15%. When it came to race, the tech giant is predominantly white (49.8%). Globally, the Uber workforce is 30.9% Asian, 8.8% Black, 5.6% Hispanic, and 4.3% Multiracial.

While its diversity numbers weren’t particularly surprising, the tech giant fared slightly better than Facebook and Apple. Women make up 36% of Uber’s global workforce, whereas Facebook and Apple were both at 32% female representation last year.

Following the release of the report, Uber announced it would pledge $3 million over the next three years to support organizations working to bring women and underrepresented groups into tech. It also said it would ramp up its presence at recruiting events around the country and continue its outreach to Historically Black Colleges and Universities and Hispanic Serving Institutions.

More recently, former U.S. Attorney General Eric Holder concluded his internal investigation of Uber and recommended that the tech giant “elevate the visibility of Uber’s current head of diversity” and “regularly publish diversity statistics.”

In response to the CBC’s letter, an Uber spokesperson told Fortune that the company is “committed to making Uber a more diverse and inclusive workplace at all levels of the organization, and we’ll continue to engage with community leaders like the CBC as we work to achieve this important goal.”