The World Health Organization (WHO) said on Tuesday that it was conducting checks with Russian authorities after the death of a laboratory technician at the Institute for Plague Control in the Irkutsk region of Siberia.

"The initial risk assessment carried out by the WHO, based on the available information, indicates that the risk is moderate to low for Irkutsk, low for the Russian Federation as a whole and very low for the European region," said WHO spokesman Christian Lindmeier at a press briefing in Geneva.

The WHO has contacted Russian health authorities "to verify the event, its circumstances, ongoing laboratory analyses and results", and indicated that it has offered its assistance.

The death of Daria Chipilova, a 28-year-old laboratory technician who worked for the Irkutsk Institute for Plague Control, reported by several Russian media outlets on October 2, has sparked serious concerns in Russia and beyond.

According to the media outlet Peoples of Baikal, she may have contracted pneumonic plague after a test tube broke, but Russian authorities are tempering suspicions of contamination from this infectious disease caused by bacteria.

Regional Governor Igor Kobzev stated on Monday that post-mortem analyses conducted by a special commission of experts from Rospotrebnadzor indicate that the young woman died of "pneumonia" of "undetermined" origin.

According to the investigation, "no microorganisms linked to the young woman's professional activity were detected in her biomaterials," he said.

Russian authorities also told the WHO that "according to test results, no pathogen responsible for dangerous infectious diseases was detected in people who had been in contact," Lindmeier also reported.

Pneumonic plague is highly contagious and can be fatal if not treated quickly, according to the WHO.