WHO chief Tedros Adhanom Ghebreyesus on Sunday declared the outbreak a public health emergency of international concern (PHEIC) -- the second-highest level of alert under international health regulations.

Some 88 people have died from the highly contagious haemorrhagic fever in the DR Congo, with one death in Uganda, and at least 336 suspected cases.

An Ebola outbreak in the Democratic Republic of the Congo and Uganda constitutes a "public health emergency of international concern," the World Health Organization said.