Hours before President Barack Obama used the shooting rampage at an Oregon community college to call for stronger gun control, Republican candidate Ben Carson warned against doing so and said that a greater focus on addressing mental-health issues was necessary.

"Obviously, there are those who are going to be calling for gun control," Carson said on "The Hugh Hewitt Show" of the attack that killed at least 13 people and injured as many as 20 others at Umpqua Community College in rural Roseburg.

The 20-year-old shooter was killed by police gunfire.

Later at the White House, President Barack Obama urged stricter gun controls.

"Somehow this has become routine," he said. "We can actually do something about it, but we're going to have to change our laws.

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

But that's the wrong focus, Carson told Hewitt.

"Obviously, that’s not the issue," he said. "The issue is the mentality of these people."

The retired pediatric neurosurgeon said that the focus should not be on guns but on "early warning clues" to prevent such attacks.

"What I worry about is when we get to the point where we say we need to have every gun registered," he said. "We have to know where the people are and where their guns are, that’s very dangerous.

"And that I wouldn’t agree with at all."