The head of the World Health Organization (WHO) has ordered an internal investigation into allegations of racism, sexism and misconduct at the United Nations agency. 

WHO Director-General Tedros Adhanom Ghebreyesus confirmed to The Associated Press on Thursday he ordered the investigation last month into allegations laid out in a series of anonymous emails. 

{mosads}The emails from an unnamed source claimed that African staffers at WHO have faced “systematic racial discrimination,” and also accused WHO senior officials of “attempting to stifle” investigations into Ebola funds that were allegedly misspent, according to the AP.

The anonymous emails accused WHO of “crooked recruitment and selection” processes that are “tantamount to fraud, corruption and abuse of authority,” the AP reported.

Tedros has instructed David Webb, the director of WHO’s office of internal oversight, to conduct an investigation into the claims.

Webb said he and his team will investigate those claims as well as 150 others that have been reported to his office in the past year, according to the AP.

The anonymous author of one email, which was sent to WHO directors in April, claimed African staffers are “abused, sworn at (and) shown contempt to” by their colleagues.

Another called out a senior doctor who helped lead the response to Ebola, calling his conduct “unacceptable, unprofessional and racist,” according to the AP. The anonymous author said the doctor “humiliated, disgraced and belittled” a WHO staffer from the Middle East at a meeting.

Oyewale Tomori, a Nigerian who serves on several of WHO’s advisory boards, told the AP that he has “no doubt” the claims in the email are true. 

“After what I’ve seen at WHO, I have no doubt that everything in those emails is true,” Tomori, who used to work at WHO, said. He said he and other African staffers faced the brunt of “slights that turned to slurs, embarrassing humiliations and rudeness that escalated to abuse” at the UN agency.