According to the report, Health minister Oly Ilunga late on Wednesday said that two suspected cases of haemorrhagic fever were reported in the Wangata health zones, which includes Mbandaka city, about 150 kilometres (93 miles) from Bikoro, the rural area where the outbreak began.
The WHO is anxious about the disease reaching the city of Mbandaka with a population of about 1 million people, which would make the outbreak far harder to tackle.
He said authorities would intensify population tracing at all air, river and road routes out of the city.
It is the ninth time Ebola has been recorded in the DRC.
The Ebola outbreak in the Democratic Republic of Congo has spread to a city, the World Health Organization said Thursday, raising concern the deadly virus may prove tougher to contain.
Ebola is most feared for the internal and external bleeding it can cause in victims owing to damage done to blood vessels.
The announcement came just as thousands of doses of the experimental Ebola vaccine arrived in the country, with vaccinations expected to commence this coming weekend.
Until now, all the confirmed Ebola cases were reported from Bikoro health zone, which is also in Equateur Province but at a distance of almost 150 km from Mbandaka.
The minister has confirmed that three case of Ebola have been detected so far in the urban area.
As of 15 May, a total of 44 Ebola virus disease cases have been reported: 3 confirmed, 20 probable, and 21 suspected. Vaccine for curing Ebola has not been discovered yet.
More than 11,300 people were confirmed dead between March 2014 and January 2016 in Liberia, Guinea, Sierra Leone, Nigeria, the USA, and Mali. The health body also sent 300 body bags for safe burials in affected communities.
The vaccine requires storage at a temperature between -60 and -80 degrees C, tricky in a country with unreliable electricity.