The statement , which did not mention President
Donald Trump directly, also reminded Americans that "we are not helpless" in the face of the nation's high frequency of mass shootings compared to other countries.
"And until all of us stand up and insist on holding public officials accountable for changing our gun laws, these tragedies will keep happening," Obama wrote.
A
shooting at a Walmart in El Paso,
Texas, on Saturday killed 22 people, and a second shooting outside a crowded bar in Dayton, Ohio, early Sunday killed nine people.