MOSCOW, August 3 (RIA Novosti) - Russia will tighten its borders following an outbreak of pneumonic plague in the Chinese Qinghai Province, Russia's Chief State Health Inspector Gennady Onishchenko said on Monday.

Chinese authorities have quarantined the town of Ziketan in the northwest of the country after an outbreak of pneumonic plague which has killed two and infected another 10 people.

Onishchenko said that the possibility of the infection making its way to Russia can not be excluded.

"Control over Russians and Chinese crossing the border will be tightened," he said adding that there are few visitors to the area at the moment.

He also said that how the infection is being transmitted is unclear and it "needs to be studied. It is not clear why it is a pneumonic plague. Normally, it begins with a bubonic plague," he said.

"I think we will discuss it with our Chinese colleagues," Onishchenko added. He also confirmed the Chinese decision to quarantine the town.

According to the World Health Organization, pneumonic plague is "the most virulent and least common form of plague." The disease is spread mainly among small animals and their fleas and can be transmitted from human to human through inhalation of infected droplets.