WATCH: Obama calls for stricter gun control: ‘Our thoughts and prayers are not enough’
Obama (ABC News)

President Barack Obama on Thursday angrily called for stricter U.S. gun laws after the latest mass murder in Oregon and took aim at the powerful National Rifle Association gun lobby for blocking reform.

Appearing in the White House briefing room with a grim expression and an angry tone, Obama said it was not enough to offer prayers after major shootings continued to occur regularly throughout the country.

"As I said just a few months ago, and I said just a few months before that, and I said each time we see one of these mass shootings, our thoughts and prayers are not enough," Obama told reporters after the latest shooting at a community college in which 13 people were killed and some 20 people were wounded.

"It's not enough," he said.

Nodding to the arguments that such shootings are often committed by the mentally ill, Obama said it was clear that anyone who commits such crimes had a "sickness in their minds."

"But we are not the only country on Earth who has people with mental illnesses who want to do harm to other people," he said. "We are the only advanced country on Earth who sees these kinds of mass shootings every few months."

Obama spoke mainly without notes, angrily anticipating the arguments that gun advocates would brandish in the wake of the shooting. He said he knew his opponents would criticize him for politicizing a tragedy.

“This is something we should politicize,” he said, calling on Americans of all political stripes to hold their elected leaders accountable for acting on the issue.

Obama called on gun owners who use weapons for hunting, sport and protection to question whether the gun lobby represented their views. He did not mention the National Rifle Association by name, but his comments were clearly directed at that organization, which has broad political influence in Washington.

Obama and Vice President Joe Biden made a concerted push for broad gun control reforms after the 2012 Newtown, Connecticut school shooting of young children that shocked the country. They were unsuccessful.

Obama said he would continue to bring up the need for reform every time such a shooting took place, but the White House has made clear that it was unlikely to attempt another broad push on gun control through the Republican-led U.S. Congress.

(Reporting by Jeff Mason and Roberta Rampton; Editing by Sandra Maler and Jonathan Oatis)