Four people, including a diplomat from the U.S. Embassy in Moscow, have been injured in an apparent gas explosion.
Russian Emergency Ministry spokesman Viktor Biruykov said the incident took place in an apartment block on Moscow's Kutuzov Avenue on May 22.
The blast sprayed glass shards and metal fragments over a wide swath and left a sizeable crack in the building's brick facade.
Two of those injured, including a female U.S. national in her late 40s, were hospitalized.
Doctors say the American woman -- whose name was not released -- has been placed into an artificial coma.
Based on reporting by RIA Novosti, Interfax, AP, and ITAR-TASS