Mr Ghebreyesus said that it was the largest first-month caseload of any Ebola outbreak in Africa.
Authorities have also reported attacks on burial teams and treatment centres involved in the response.
A police spokesman said ten bodies have been recovered since the collapse in a remote area on Sunday.
Africa CDC said a new variant has also emerged, raising fresh concerns.
The crisis has displaced hundreds of thousands of people in eastern DRC, with 10,000 to 15,000 fleeing into Burundi in just a few days, according to UNHCR.
UNICEF has issued a warning over escalating violence in the eastern Democratic Republic of Congo and its impact on children.
“For decades, the Congolese people have been living through a storm of crises.”
