WASHINGTON — A visibly frustrated President Obama said Thursday that thoughts and prayers are no longer enough as Americans respond to another deadly school shooting, and he challenged voters to elect officials who will do something.

Obama addressed the nation from the White House after at least 10 people were killed by a 20-year-old gunman at Umpqua Community College in Oregon.

Mass shootings have become embedded in the arc of Obama’s presidency. He’s traveled to Aurora, Colorado; Tucson, Arizona; Charleston, South Carolina, and numerous other cities to mourn victims of gun violence.

Obama said the nation’s response to mass shootings has become routine – from the reporting by the media, to his own comments, to the opposition to legislative changes aimed at deterring the violence.

Obama said it’s clear that anyone responsible for such carnage has a sickness in his mind. He said other nations also have mentally ill residents who want to harm others, but the United States is alone in the sheer depth of the problem.

“We are the only advanced country on earth that sees these kinds of mass shootings every few months,” Obama said.

Obama has sought changes in the nation’s gun laws, although it’s unclear whether the changes often proposed – expanded background checks, stricter magazine limits and an assault weapons ban – would have prevented Thursday’s massacre.

“It cannot be this easy for somebody who wants to inflict harm on other people to get his or her hands on a gun,” he said.

The White House’s failed push for gun control legislation after the 2012 Newtown, Connecticut, shooting – in which 20 children and six adults were killed at an elementary school – deeply frustrated Obama. With little change in Washington’s political dynamic, he hasn’t made a concerted effort to renew the gun control effort.

“I’d ask the American people to think about how they can get our government to change these laws and to save lives and to let young people grow up, and that will require a change of politics on this issue,” Obama said.

Obama said there is a gun for roughly every man, woman and child in the U.S. He asked how anyone with a straight face can make the argument that more guns will make people safer.