U.S. President Barack Obama has announced strict new sanctions against Iran and Syria.
Speaking at the Holocaust Museum in Washington on April 23, Obama said the world must never again allow hatred to take root and spawn the "madness" of mass atrocities.
Obama told Holocaust survivors and their families that "national sovereignty is never a license to slaughter" people.
He said the "work will never be done" in preventing atrocities.
Obama said the United States has placed new sanctions on people and entities in Iran and Syria who use technology to target citizens and erode their human rights.
Obama also announced a posthumous Presidential Medal of Freedom for former Polish underground officer Jan Karski, who was among the first people to provide accounts of the Holocaust to the world during World War II.
With reporting by AP