The Democratic Republic of Congo has confirmed the first case of Ebola in the eastern city of Goma, home to more than a million people.
The health ministry confirmed that a pastor tested positive for the virus in a centre in Goma after arriving there by bus on Sunday.
The ministry says that risk of the disease spreading is low.
More than 1,600 people have died since the Ebola outbreak began in eastern DR Congo a year ago.
The pastor travelled 200 km (125 miles) to Goma by bus from Butembo, where he had been with people with Ebola.
The health ministry said in a statement: “Due to the speed with which the patient has been identified and isolated, as well as the identification of all passengers from Butembo, the risk of spreading to the rest of the city of Goma remains low.”
It said that the bus driver and 18 other passengers would be vaccinated on Monday.
Goma is a major commercial and cultural hub on DR Congo’s border with Rwanda, with transport links to the wider country and region. Its health ministry has been preparing for an outbreak.
In November last year, it launched preparation and response activities. Three thousand health workers in the city have already been vaccinated.
The current outbreak in eastern DR Congo began in 2018 and is the 10th to hit the country since 1976.
It is dwarfed by the West African epidemic of 2014-16, which affected 28,616 people mainly in Guinea, Liberia and Sierra Leone. About 11,310 people died in what was the largest outbreak of the virus ever recorded.
Ebola infects humans through close contact with infected animals, including chimpanzees, fruit bats and forest antelope.
It can then spread rapidly, through contact with even small amounts of bodily fluid of those infected – or indirectly through contact with contaminated environments.