The latest figures released by the Health Ministry on Thursday showed that 4,018 people have died, making up nearly half of the 8,300 confirmed cases, in what has become the fastest-growing Ebola outbreak in history.

Congo announced an outbreak on May 15, caused by the rare Bundibugyo virus, which has no known treatment or vaccine.

Some health workers gathered in Bunia, the capital of northeastern Ituri province, the heart of the outbreak. They were demanding payment for wages owed but were quickly dispersed by officials. The protesting workers included surveillance team members, who identify people exposed to infected patients. They waved placards saying, "No money, no data!" and "No payment for months."

Front-line workers have gone on strike several times since the outbreak began, further hampering efforts to contain the disease.

A senior U.N. official said that an Ebola-hit camp housing a transit center for infected patients was burned by soldiers earlier this week as they were looking for weapons in Kigonze, on the outskirts of Bunia, forcing 19,000 people in the camp to flee.