At least 131 people have died in a worsening Ebola outbreak in the Democratic Republic of Congo as health officials warned the virus was spreading into new areas.

Authorities said more than 513 suspected infections had been recorded, with confirmed cases now reported in Nyakunde in Ituri Province, Butembo in North Kivu and the eastern city of Goma.

The outbreak has also crossed into Uganda, where officials confirmed two Ebola cases and one death.

The World Health Organization declared the outbreak an international emergency, warning the situation could become far larger than currently detected.

Health officials said the outbreak involved the Bundibugyo strain of Ebola, which has no approved vaccine or treatment.

An American doctor working in eastern DR Congo was among those infected during the outbreak. The doctor, identified by missionary group Serge as Peter Stafford, was being evacuated to Germany for treatment after testing positive for the virus.

The US Centers for Disease Control and Prevention said several other Americans exposed during the outbreak were also being monitored and evacuated from the region.

The agency announced tighter screening measures for travellers arriving from affected countries and warned against travel to DR Congo.

Africa CDC director-general Jean Kaseya urged communities to follow public health measures, particularly during funerals, saying unsafe burial practices had contributed to previous Ebola outbreaks.

Neighbouring countries including Rwanda and Nigeria said they were increasing border screening and surveillance as fears of regional spread intensified.

The outbreak has revived concerns over a repeat of the devastating 2014-2016 West Africa Ebola epidemic, which killed more than 11,000 people.

Erizia Rubyjeana