The World Health Organization says the Ebola outbreak in the Democratic Republic of Congo has spread to a city, raising concern the deadly virus may prove tougher to contain.

The UN’s health agency said in a statement that one new case of Ebola virus disease has been confirmed in Wangata, one of the three health zones of Mbandaka, a city of nearly 1.2 million people in Equateur Province in northwestern Democratic Republic of the Congo.

According to WHO, forty-four cases have been reported so far, including three confirmed, 20 probable and 21 suspected.