The World Health Organization has held back from declaring the Ebola epidemic in the Democratic Republic of Congo an international emergency despite the virus crossing into neighboring Uganda earlier this week.

The UN agency convened its expert emergency committee on Friday and was expected to upgrade the status of the outbreak to a “public health emergency of international concern” - its highest alert level.

However, in a statement on Friday evening it said the epidemic does not yet merit being declared a global emergency and instead described it as "an extraordinary event" of deep concern.

Dr Preben Aavitsland, the acting chair of the committee, said the outbreak was "a health emergency in the Democratic Republic of the Congo" but the situation did not yet meet the criteria for being declared a global emergency.

To be declared a global emergency, an outbreak must constitute a risk to other countries and require a coordinated international response, according to the WHO.

WHO director general Tedros Adhanom Ghebreyesus, who is in DRC reviewing the Ebola response, said he accepted the committee's advice.

"Although the outbreak does not at this time pose a global health emergency, I want to emphasise that this outbreak is, for those affected, very much an emergency," he said.