I send my deepest condolences to the people of Russia after the terrible loss of life and injuries resulting from the bombings on the Moscow Metro. The American people stand united with the people of Russia in opposition to violent extremism and heinous terrorist attacks that demonstrate such disregard for human life, and we condemn these outrageous acts. My thoughts and prayers go out to those who lost loved ones, and I wish all who sustained injuries a successful recovery.
Note: The Office of the Press Secretary also released a Spanish language version of this statement.
Barack Obama, Statement on the Terrorist Attacks in Moscow, Russia Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/287974