- Russia is believed to have imposed a lockdown on hospitals and medical centres in a 30-square-mile area following a feared plague outbreak. Panic broke out when a female laboratory technician died and hundreds of people she came into contact with were placed in quarantine. Darya Shipilova, 28, was said to be working at the Irkutsk Anti-Plague Institute in Siberia when she was exposed to pneumonic plague. Ms Shipilova told medical staff she had accidentally broken a test tube holding live bacteria, according to the news outlet Lyudi Baikala. Other countries have tightened border health controls despite Russia's insistence that the plague researcher died from 'unidentified pneumonia', rather than the suspected 'Black Death' bacterium. US Secretary of State Marco Rubio said today that Washington was monitoring reports of a plague infection, but that it was not a 'cause for alarm'. 'There's very limited travel between the US and Russia, obviously, but like anything else, something like that gets out, it could quickly spread,' Mr Rubio told reporters before taking off on a visit to Iceland. 'So we're watching and monitoring it closely. I don't think it's cause for alarm, but it is cause for focus and a cause to just keep an eye on it. And we're doing that.' Vladimir Putin's regime is seeking to downplay Ms Shipilova's death on October 1, yet widespread suspicion of a state cover-up is rapidly spreading. It was revealed today that more than 60 colleagues of the young scientist will remain locked inside her Siberian research institute for days, sleeping on floors and chairs despite none testing positive for the plague. Up to five hospitals in the Irkutsk area are in 'epidemic' mode, according to reports, with hundreds of staff and patients barred from leaving. City Clinical Hospitals No1, No3, and No10 and the Ivano-Matreninskaya Children's Hospital have been closed for a three-week quarantine, according to Lyudi Baikala. Relatives of a woman giving birth