China has sealed off parts of its northwestern city of Yumen after a resident died of bubonic plague last week, according to state media.
A 38-year-old victim was infected by a marmot, a wild rodent, and died on 16 July.
Several districts of the city of about 100,000 people in Gansu province were subsequently turned into special quarantine zones, the Xinhua agency said.
It said 151 people who came into direct contact with the victim were also placed in quarantine. None have so far shown any signs of infection, the news agency said.
The city had set aside one million yuan (€120,000) for emergency vaccinations, according to the Jiuquan Daily local newspaper.
The plague is a bacterial disease spread by the fleas of wild rodents such as marmots.
While the disease can be effectively treated, patients can die 24 hours after the initial infection, the World Health Organisation says.
Outbreaks in China have been rare in recent years, and most have happened in remote rural areas of the west.
China's state broadcaster said there were 12 diagnosed cases and three deaths in the province of Qinghai in 2009, and one in Sichuan in 2012.
Beijing's disease control centre sought to dispel worries about a wider outbreak of the disease in China.
It said on its website that the risk of the disease spreading to the capital was minimal.