The World Health Organization (WHO) has declared the Ebola crisis in the Democratic Republic of Congo (DRC) a public health emergency of international concern.
But it stressed borders should not be closed, adding that the risk of the disease spreading outside the region was not high.
The outbreak in the DRC has killed more than 1,600 people.
This week, the first case was detected in Goma, home to more than a million.
WHO chief Tedros Adhanom Ghebreyesus told a news conference in Geneva said “It is time for the world to take notice,”.
He said he had accepted the advice of his advisory board to invoke the emergency provision PHEIC, which has only been used by the United Nations health agency four times previously. This includes the Ebola epidemic that devastated parts of West Africa from 2014 to 2016 and killed more than 11,000 people.
He added that he had also accepted recommendations which stressed there should be no restrictions on travel or trade, and no entry screening of passengers at ports or airports outside the immediate region.
The International Federation of Red Cross and Red Crescent Societies welcomed the move..
The outbreak, the second largest in history, started in August 2018 and is affecting two provinces in DRC – North Kivu and Ituri.
More than 2,500 people have been infected and two-thirds of them have died.
It took 224 days for the number of cases to reach 1,000, but just a further 71 days to reach 2,000 with about 12 new cases are being reported every day.