The World Health Organization has raised concerns that continuing conflict in parts of the Democratic Republic of Congo is hampering efforts to contain the Ebola outbreak even as local health authorities confirmed the spread of the virus to another province in the eastern part of the country.

The toll of the deadly virus has inched up to 73 cases including 46 confirmed and 27 probable, exceeding the 54 cases that were reported in western Congo and was declared over at the end of July. At least 42 people are confirmed dead and 40 cases are under investigation as a new treatment center in Beni, a major city in North Kivu, began operation and vaccination exercises launched in Ituri. This is the second province affected after North Kivu.

The new case is of an infected person who returned home after being treated for heart problems at Mangina Reference Health Center, where five new confirmed cases－four health workers and a patient－have been recorded.

While briefing journalists in Geneva on Tuesday over his recent visit in the central African country, WHO Director General Tedros Adhanon Ghebreyesus warned that the ongoing conflict in the North Kivu province was aiding the spread of the deadly virus.

He said that the region, sprinkled with so-called "red zones" due to the fighting, might be hiding places for the Ebola virus and making it difficult for responders to enter and for infected residents to seek outside help.

There are more than 100 armed groups in the province and about 120 violent incidents since January alone, Tedros said, adding that there was fighting within 15 kilometers of where he stayed in Beni during his trip to the country.

Calling for a cease-fire between the groups, Tedros said the virus is not selective. "We call on the warring parties for a cessation of hostilities, because the virus is dangerous to all. It doesn't choose between this group or that group," he said.

The area poses a challenge for the WHO and partners to deliver urgently needed support due to a high population density and movement in the region, which has already hosted more than 1 million internally displaced people. Although this is Congo's 10th Ebola outbreak, health officials have said the local population is not familiar with the disease. That makes outreach more challenging.

Tedros confirmed that the WHO has started a vaccination operation in the outbreak area, with five patients already given mAb114 therapy, the first time it has been deployed against an active outbreak. There are already more than 3,000 vaccines on the ground, which could be bumped up to 300,000 in a short notice he said and added that four other experimental treatments have been approved for use.

Health authorities are using what is called a ring vaccination technique in which health workers are vaccinated first, along with contacts of Ebola patients and their contacts. At least 200 health workers have been vaccinated. The WHO chief said the risk of international spread is low. He said officials have been in contact with neighboring Uganda, Rwanda, Burundi and South Sudan.