The deadly Ebola outbreak in the Democratic Republic of Congo is now an international health emergency, the World Health Organisation has announced.
Wednesday's announcement comes after the virus spread this week to a city of two million people .
A WHO expert committee had declined on three previous occasions to advise the UN health agency to make the declaration for this outbreak, which other experts say has long met the conditions.
More than 1600 people have died since August in the second-deadliest Ebola outbreak in history, which is unfolding in a region described as a war zone.
This week the first Ebola case was confirmed in Goma, a major regional crossroads in the Democratic Republic of Congo's northeast, on the Rwandan border, which has an international airport.
Health experts have feared this scenario for months.
A declaration of a global health emergency often brings greater international attention and aid, along with concerns that nervous governments might overreact with border closures.
While the risk of regional spread is high, the risk outside the region remains low, WHO chief Tedros Adhanom Ghebreyesus said after the announcement in Geneva.
"The (international emergency) should not be used to stigmatise or penalise the very people who are most in need of our help," he said.
This is the fifth such declaration in history. Previous emergencies were declared for the devastating 2014-16 Ebola outbreak in West Africa that killed more than 11,000 people, the emergence of Zika in the Americas, the swine flu pandemic and polio eradication.
WHO defines a global emergency as an "extraordinary event" which constitutes a risk to other countries and requires a co-ordinated international response.
Last month this outbreak spilled across the border for the first time when a family brought the virus into Uganda after attending the burial of an infected relative in the Congo.
Even then, the expert committee advised against a declaration.
Alexandra Phelan, a global health expert at Georgetown University Law Centre, said Wednesday's declaration was long overdue.
"This essentially serves as a call to the international community that they have to step up appropriate financial and technical support," she said, but warned that countries should be wary of imposing travel or trade restrictions.
"Those restrictions would actually restrict the flow of goods and health care workers into affected countries so they are counter-productive," she said.
Future emergency declarations might be perceived as punishment and "might result in other countries not reporting outbreaks in the future, which puts us all at greater risk".
Australian Associated Press