"This is becoming the norm," he continued about school shootings. "We should be ashamed."
The President addressed lawmakers who blame mass shootings on mental health, not access to guns.
"The United States does not have a monopoly on crazy people. It's not the only country that has psychosis. And yet, we kill each other in these mass shootings at rates that are exponentially higher than any place else," he said.
Obama said that he could only do so much from the executive branch and urged people to call on Congress to pass gun control legislation, criticizing lawmakers who are "terrified of the NRA."
"If public opinion does not demand change in Congress, it will not change," he said.