Fears of a wider regional spread are growing after Ebola reached a sixth province in the Democratic Republic of Congo, with neighboring South Sudan also at risk.

The outbreak, centred in conflict-hit Ituri province, has already become the largest Ebola outbreak recorded in the DRC and is on course to become the country's deadliest.

Declared on May 15, the outbreak is thought to have already been spreading for several weeks and is the DRC's 17th Ebola outbreak.

The country's previous deadliest outbreak, between 2018 and 2020, killed nearly 2,300 people from about 3,500 recorded cases.

The current outbreak has killed more than 2,128 people, with 4,566 confirmed cases, according to authorities.

Until now, cases had been reported in five provinces: Ituri, which borders Uganda and South Sudan, North Kivu, South Kivu, Haut-Uele and Tshopo.

A person has died of Ebola in northern Bas-Uele province after traveling from neighbouring Haut-Uele, Jean Kaseya, head of the Africa Centres for Disease Control and Prevention, told reporters on Thursday.

Africa CDC said the virus was spreading at an unprecedented rate.

In the first three months of the outbreak, the DRC recorded seven times more cases and five times more deaths than were reported during the same period of the 2014 West Africa Ebola outbreak, the largest in history, Africa CDC said.

The World Health Organization said on Wednesday it hopes to contain the spread of Ebola in the DRC within three months.

But Mercy Corps warned on Thursday that the virus could spread into neighbouring South Sudan, which shares borders with the DRC's Ituri and Haut-Uele provinces.

“Confirmed cases are now just 35 kilometres (22 miles) from the South Sudan border, along high-risk travel corridors,” the organisation said in a statement.

The response in the DRC is hampered by stretched health services, insufficient clean water and safe toilets, fragile trust and insecurity, it added.

Some of the affected provinces are densely populated and have only a weak government presence and largely lack health infrastructure.