Daughter (1) and wife of Ebola victim now infected
The one-year-old daughter of a man who died of Ebola in a major city of the Democratic Republic of Congo has contracted the disease.
His wife has also been infected.
Neighbouring Rwanda briefly closed its border over the virus outbreak which has entered its second year.
It is the first transmission of the disease inside Goma, a city of more than two million people on the Rwandan border, a scenario health experts have long feared.
The painstaking work of finding, tracking and vaccinating people who had contact with the man, and the contacts of those contacts, has begun.
He died on Wednesday after spending several days at home with his large family while showing symptoms.
DR Congo's presidency said the entire family was at "high risk" and it was likely other members will be confirmed to have Ebola.
"We're seeing the first active transmission chain in Goma and expect more to come," the International Rescue Committee's Ebola response director, Andre Heller, warned.
This outbreak has killed more than 1,800 people, nearly a third of them children.
It is now the second-deadliest Ebola outbreak in history, and the World Health Organisation (WHO) has declared it a rare global emergency.
Rwanda's State Minister for Foreign Affairs Olivier Nduhungirehe confirmed the border closure, a day after WHO officials praised African nations for keeping their borders open.
Last week Saudi Arabia stopped issuing visas to people from Congo while citing the Ebola outbreak, shortly before the annual hajj pilgrimage there this month.
DR Congo condemned Rwanda's decision, and local Congolese at the busy border expressed frustration.
"I can't understand why they don't just test us instead of closing these borders," said Angel Murhula, who works in Rwanda. Several hours later the border had reopened.
A Rwanda health ministry statement called the events a "traffic slowdown" as surveillance for Ebola was reinforced.
It advised against unnecessary travel to the Goma area.
WHO says the risk of regional spread is "very high".
The death on Wednesday in Goma "in such a dense population centre underscores the very real risk of further disease transmission, perhaps beyond the country's borders", United Nations agencies said.
The man in his 40s was a miner returning from the north-eastern Ituri province where no Ebola cases in this outbreak have been recorded, WHO said.
He was exposed along the roughly 480km route to Goma as he took taxis over a number of days through the densely populated region at the heart of the outbreak.