US watches Russian lab technician's death at plague center 'very seriously'

US President Donald Trump said the US is monitoring "very seriously" the case of a Russian lab technician found dead at a plague research center in Siberia, amid concerns about a potential pneumonic plague outbreak. Secretary of State Marco Rubio said Washington is closely watching the situation, noting the infection could spread rapidly if it escapes the lab, though he said there is no reason for panic. Russian officials attributed the death to pneumonia from unknown causes and said no pathogen was confirmed in the woman's biological samples. The technician, identified as Daria, was around 20 years old and had recently visited Buryatia, where plague is endemic in marmots. The institute was established after a 1920s outbreak, and experts note pneumonic plague is treatable with antibiotics but can spread person-to-person.