U.S. President Barack Obama has issued a proclamation to mark the eleventh anniversary of the Sept. 11, 2001 terrorist attacks.

In the proclamation released by the White House on Monday, Obama remembered the victims, their families, and the heroes who stood up during one of the country's darkest moments.

The president invited U.S. citizens to join community memorial services for the victims and ordered all government agencies to fly the U.S. flag at half-staff on Sept. 11.