Authorities in China have stepped up precautions after a city in the Inner Mongolia autonomous region confirmed one case of bubonic plague.

According to state reports, the Bayannur patient - a herdsman - is in quarantine and in a stable condition.

Officials said they were also investigating a second suspected case. The bubonic plague was once the world"s most feared disease, but can now be easily treated.

The first case was reported as suspected bubonic plague on Saturday at a hospital in Urad Middle Banner, in Bayannur city. It is not yet clear how or why the patient might have become infected.

The second suspected case involves a 15-year-old, who had apparently been in contact with a marmot hunted by a dog.