NEW: State Department officials are closely monitoring reports of a suspected pneumonic plague death in Siberia after a lab accident involving live bacteria. A 28-year-old lab worker reportedly became infected after a test tube broke while she was collecting samples. Foreign officials have not disclosed the full extent of the potential exposure, but nearly 200 people are now being monitored as a precaution. Secretary of State Rubio says that it's not cause for alarm at this time, but reiterated that his team is actively monitoring it. Pneumonic plague can be treated with common antibiotics, especially when treatment begins early, according to one official.