The head of the World Health Organization said on Monday that the fast-moving Ebola outbreak in the Democratic Republic of Congo and Uganda was outpacing response efforts, giving the latest number of suspected deaths as 220.

Addressing an online meeting of the African Union about the outbreak, WHO Director-General Tedros Adhanom Ghebreyesus said a delay in detecting Ebola cases meant responders were now “playing catch-up” and the epidemic was likely to get worse before it gets better.

Tedros said he would travel to Congo – the epicenter of the outbreak – on Tuesday with another senior WHO official responsible for addressing health emergencies, Chikwe Ihekweazu.

Earlier on Monday, neighboring Uganda reported two more Ebola cases, taking its total number of confirmed cases to seven, and Tedros said other countries bordering Congo were at high risk and should take immediate action.

The WHO has declared the outbreak of the rare Bundibugyo strain of Ebola a public health emergency of international concern.

Tedros said containing the fast-moving outbreak was complicated by the fact that Congo’s Ituri and North Kivu provinces were highly insecure, and there were no approved vaccines for the Bundibugyo virus.