A senior World Health Organization (WHO) official told a briefing in Geneva on Tuesday that the Ebola outbreak in the Democratic Republic of Congo (DRC) had the highest number of confirmed cases in its first month of any Ebola outbreak in Africa.

Officials have confirmed as of Monday more than 1,000 cases and 267 deaths from the current outbreak of the comparatively rare Bundibugyo ebolavirus.

The WHO formally confirmed the outbreak on May 15, but experts believe it had been likely circulating for weeks or months prior to that.

Dozens of cases confirmed at eastern Congo displacement camps

"The response needs to expand to keep pace with the expanding outbreak — this is beginning to happen," the WHO's Abdirahman Mahamud said after returning from a visit last week to the Bunia treatment center in the outbreak's epicenter. Cases have now also been confirmed in at least three of war torn eastern Congo's crowded displacement camps.