The Democratic Republic of Congo ( DRC ) has announced a new outbreak of the deadly Ebola virus, just days after a recent emergence of the disease, which killed 33 people, was declared over.

Four cases of the virus were confirmed in northeastern North Kivu province, the DRC's health minister said in a statement on Wednesday, though there was no indication they were linked to the country's previous - and ninth - Ebola outbreak in northwestern  Equateur Province.

"Although we did not expect to face a tenth epidemic so early, the detection of the virus is an indicator of the proper functioning of the surveillance system,"Health Minister Oly Ilunga said.

Ebola is a virus-caused haemorrhagic fever that in extreme cases causes fatal bleeding from internal organs, the mouth, eyes or ears.

Four confirmed cases

North Kivu authorities alerted the health ministry on Saturday that 26 cases of hemorrhagic fever, including 20 deaths, had occurred  in and around Mangina, a town about 30km west of the city of Beni and 100km from the DRC's border with Uganda.

Six samples were taken from hospitalised patients and sent to the National Institute of Biological Research in Kinshasa, the capital, for analysis. Four of the samples tested positive for the Ebola virus.

A team of 12 experts from the health ministry will arrive in Beni on Thursday to set up a response operation, the ministry said, and local travel restrictions were being implemented. 'A constant threat'

Tedros Adhanom Ghebreyesus, director general of the World Health Organization (WHO), said in a tweet on Wednesday that health officials would continue to fight the "constant threat" of Ebola in the DRC.

The latest outbreak comes after DRC authorities  declared  a previous emergence of the disease - which has no proven cure - over on July 24.

The declaration brought the curtain down on an outbreak which began two months earlier  in the remote northwestern area of Bikoro, about 2,000km from Mangina, on May 8 and culminated in 54 confirmed cases of Ebola, 33 of which proved fatal.

Health officials said a quick international response and the vaccination of more than 3,300 people were decisive factors in containing the virus.

The outbreak took place fewer than 12 months on from the DRC's previous Ebola  scare, in May 2017, during which eight people were infected, four of whom died.

The average fatality rate among those infected with Ebola is about 50 percent,  according to the WHO.

An epidemic of the virus killed about 11,300 people in West Africa as it surged through Guinea, Sierra Leone, and Liberia between 2013 and 2016.