However, the statement said the case was not linked to the two people from remote villages in Inner Mongolia who were diagnosed with pneumonic plague earlier in the month and are being treated in Beijing.
The Beijing Health Commission said on Saturday that one of the patients was now in a stable condition, while the second was in a more serious state despite having earlier shown signs of recovery.
Several of the people with whom they had been in close contact and had been quarantined had since been released from hospital after showing no signs of the disease, the authority said.
Although plague has been mostly eradicated in China, cases are occasionally reported in northern parts of the country. According to official yearbooks there have been six fatalities from the disease in the past five years.
Plague, which comes in three strains - bubonic, pneumonic and septicaemic, is categorised as the most serious contagious disease in China due to its high infection and mortality rates.
- AP, SCMP