China has sealed off a remote far-western town of 10,000 people after two people died of pneumonic plague, state media said Monday, but the World Health Organization said such outbreaks were nothing new.

Another 10 people had contracted the disease in the ethnically Tibetan region of the sparsely populated province of Qinghai, Xinhua news agency said.

The town of Ziketan and the surrounding region had been closed off, the Health Ministry said.

China experiences periodic outbreaks of plague, which is typically spread by rodents and fleas, is airborne and can spread easily between people.

But the WHO said it was not unduly concerned.

This is not new, said Beijing-based WHO spokeswoman Vivian Tan. There have been sporadic cases reported over the years. We're not surprised that it's come up. We're in constant contact with the authorities to make sure things are under control.

She also said the fact that the outbreak had occurred in a remote part of the country should help to mitigate the impact.

An official at the Qinghai government's health department said authorities were confident of keeping the outbreak under control.

There's no possibility of it spreading, said the official, who only provided his family name, Li. We have already closed off the infected area. We are currently treating those who are sick.