The World Health Organization says Ebola has spiked in Congo in recent days because of "increased security challenges," a week after its director-general predicted the outbreak might be contained within six months.

The U.N. health agency said late Thursday the recent attacks on Ebola clinics slowed response efforts for days. Congolese officials reported dozens of new suspected and confirmed cases in recent days. Last week, WHO chief Tedros Adhanom Ghebreyesus declared that Ebola was "contracting."

Doctors Without Borders has said that conditions at the outbreak's epicenter are "toxic" and that international responders have failed to convince local communities to accept their help.

Tedros Adhanom Ghebreyesus, Director-General of the World Health Organization (WHO), speaks at the European headquarters of the United Nations in Geneva, Switzerland, Thursday, March 14, 2019 about the update on WHO Ebola operations in the Democratic Republic of the Congo (DRC). (Martial TrezziniKeystone via AP)

Tedros Adhanom Ghebreyesus, Director-General of the World Health Organization (WHO), speaks at the European headquarters of the United Nations in Geneva, Switzerland, Thursday, March 14, 2019 about the update on WHO Ebola operations in the Democratic Republic of the Congo (DRC). (Martial TrezziniKeystone via AP)

WHO acknowledged that many people with Ebola are refusing to seek care at health centers and are dying at home, increasing the chances of the virus' spread.

WHO Director-General, Dr Tedros Adhanom Ghebreyesus visits an Ebola treatment centre in Butembo, in the Democratic Republic of the Congo, Saturday March 9, 2019. Armed assailants again attacked an Ebola treatment center in the heart of eastern Congo's deadly outbreak on Saturday, with one police officer killed and health workers injured. (Dalia LourencoWHO via AP)

WHO Director-General, Dr Tedros Adhanom Ghebreyesus visits an Ebola treatment centre in Butembo, in the Democratic Republic of the Congo, Saturday March 9, 2019. Armed assailants again attacked an Ebola treatment center in the heart of eastern Congo's deadly outbreak on Saturday, with one police officer killed and health workers injured. (Dalia LourencoWHO via AP)