Bunia, Congo — The Ebola outbreak in Congo has reached 5,000 cases, government data showed Wednesday, as responders warn it is spreading at an unprecedented speed outpacing efforts to slow it in one of the country’s remotest regions.

Data from Congo’s Ministry of Health showed the outbreak had so far recorded 5,021 cases, including 2,378 deaths as of Sunday, as it rages in some of the most challenging conditions imaginable fueled by insecurity, displacement and intense population movements. The outbreak is caused by the Bundibugyo species of Ebola, which has no approved vaccines or treatments.

The outbreak has infected and killed more people at a greater speed than any other outbreak in history. It is Congo’s 17th Ebola epidemic, according to the Reuters news agency.

Only a week ago, the outbreak had recorded 4,381 confirmed cases, including 2,011 deaths.

The new totals come some three months since the outbreak was declared on May 15.

Starting from the first detected case, it has spread about three times faster than an outbreak from 2014 to 2016 across West Africa, which was the deadliest Ebola outbreak on record with more than 11,000 deaths.

The outbreak “has spread rapidly and the risk of further national and international spread remains high,” World Health Organization Director-General Tedros Adhanom Ghebreyesus said Tuesday at a meeting convened by the agency.

“We must be frank: The epidemic is far from being under control,” he said.

Safety concerns have limited the response as health workers are targeted, particularly in Ituri, the province that has been hit the worst by the outbreak.

Residents attacked a health team on Monday in the territory of Aru after a suspected case was reported there. A mob set fire to an ambulance and damaged two other vehicles, according to Michael Wani, president of the Union of Cultural Associations for the Development of Ituri.