Congo’s health ministry says there are now 35 confirmed cases of Ebola in the country’s northwest, including 10 deaths confirmed from the often lethal virus.

The spread of Ebola from a rural area to Mbandaka, a city of more than 1 million people, has raised alarm as the deadly disease can spread more quickly in densely populated urban centers.

This is the ninth outbreak of the hemorrhagic fever in Congo since 1976.