According to the media outlet, a 38-year-old man infected with the bubonic plague died on Monday in Zavkhan's Tosontsengel area.
The deceased had reportedly eaten marmot meat in northern Mongolia's Khovsgol province last month. The Center for Zoonotic Diseases said, as cited by the news agency, that 25 people who were in contact with the man had tested negative for the plague.
The previous two deaths were registered in the western province of Khovd in August, and in Govi-Altai province in mid-July. There have been a total of 18 suspected cases of bubonic plague in Mongolia, four of which were lab-confirmed.
In early July, two cases of the bubonic plague were confirmed in the Inner Mongolia province of China, after which a level three alert came into force, forbidding the hunting and eating of animals that could be carrying the bubonic plague.