US monitors possible plague case in Siberia after lab worker's death

The United States is closely monitoring a possible plague case in Siberia after a female laboratory worker died at a Russian anti-plague institute, with US officials expressing caution but no panic. Secretary of State Marco Rubio said the situation warrants attention, while President Donald Trump offered Russian assistance. The 28-year-old employee fell ill at the Irkutsk institute and died two days later in a hospital, with several people reportedly in quarantine. Russian authorities stated she died of pneumonia, but the exact circumstances of her illness remain unclear, and the cause of death has not been definitively confirmed.