The governor of Irkutsk insists that a lab assistant, who died, was killed by "pneumonia of unknown origin" while the Kremlin stressed "top professionals in this field" are working on it. Reports on Friday that a 28-year-old woman named Darya Shipilova, who had been working for the anti-plague institute in Siberia's Irkutsk region, had died of plague sparked alarm. Key points and original sources are listed below.

• The governor of Irkutsk insists that a lab assistant, who died, was killed by "pneumonia of unknown origin" while the Kremlin stressed "top professionals in this field" are working on it.S1

• Reports on Friday that a 28-year-old woman named Darya Shipilova, who had been working for the anti-plague institute in Siberia's Irkutsk region, had died of plague sparked alarm.S2