The first patient to be diagnosed with Ebola in the eastern DR Congo city of Goma has died, the governor of North Kivu province said on Tuesday. The case, the first in a major urban hub in the region’s nearly year-old epidemic of the disease, has sparked deep concern in neighbouring Rwanda and at the UN.

“Unfortunately, I can confirm that the patient died,” Governor Carly Nzanzu told reporters.

The patient has been described as an evangelical preacher who had travelled from Goma to Butembo, one of the towns hardest hit by the outbreak.

While there, he preached at seven churches and regularly touched worshippers, including the sick, before taking the bus back to Goma last Friday, the health ministry said.

On his return on Sunday, he went to a clinic with a fever, was diagnosed with Ebola and sent back to Butembo, which is better geared than Goma for treating the disease, it said.

“He died during transfer by road,” Nzanzu said.

More than 1 600 people have died from Ebola since 1 August, when the haemorrhagic virus erupted in North Kivu and spread to neighbouring Ituri. Health experts fear outbreaks of contagious disease in a major city.

In cities, density of population, high mobility and anonymity make it far harder to isolate patients and trace contacts compared to the countryside. Goma is a border city of about one million people located on the northern shore of Lake Kivu, adjacent to Rwanda. It has a port that links to Bukavu and South Kivu province and an airport with flights to Kinshasa, the Ugandan capital Entebbe and Addis Ababa, the capital of Ethiopia.

The city abuts the Rwandan city of Gisenyi, and there is a high number of daily border crossings, involving workers and people who have jobs or homes on the other side of the frontier.

The UN’s World Health Organization (WHO) on Monday warned the Goma case was a “potential game-changer” in the fight to roll back the outbreak in the DRC. It said it would reconvene a key panel to see whether the outbreak required a heightened global response.

Separately, Rwanda said Monday it would step up border monitoring and urged its citizens to avoid “unnecessary” travel to the eastern DRC.

The latest epidemic is the second deadliest on record globally. The worst Ebola outbreak, striking three West African countries between 2014-2016, claimed more than 11 300 lives.