As President Obama continues his California fundraising tour, he encouraged his wealthy San Francisco friends to stop mass shootings by mobilizing for gun control.

Referring to the church shooting in Charleston, Obama insisted that mass shootings were “unique” to America because of its gun laws, adding such events don’t happen as often in other “advanced countries.”

“It’s not because there aren’t violent people or racist people or crazy people in other countries; it’s that a 21-year-old kid can’t just walk in and buy a firearm and, oftentimes, through gun shows, avoid background checks, and then act on this hatred,” he said. “And we’ve got to change that, and it’s not enough for us to express sympathy — we have to take action.”

Obama admitted that in a Republican-led Congress, it would be difficult to pass any legislation.

“It is not going to happen in this Congress, but we have to stay on it so that it does,” he said.