Republican front-runner Donald Trump says Ben Carson has been gaining on him in recent polls because the retired neurosurgeon has taken a page from the Trump playbook: making controversial statements that draw media coverage.

“He’s been getting a lot of ink on the Muslims and other things,” Trump told ABC News Wednesday. “And I guess people look at that and they probably like it. Some people thought they wouldn’t like it, but they probably do.”

Trump himself burst into the lead in GOP presidential polls after saying during his announcement speech in June that people crossing illegally into the United States from Mexico are “bringing drugs, they’re bringing crime. They’re rapists and some, I assume, are good people.”

Carson’s support has nearly doubled over the past two months, according to a Fox News poll released Tuesday that shows he is now virtually tied with Trump. The New York real estate mogul is still on top with 24% but Carson had 23%, well within the margin of error.

Carson generated a firestorm of criticism a few weeks ago when he said he didn’t believe a Muslim should be president of the United States. He later walked that back, saying he wouldn’t have a problem with a Muslim occupying the Oval Office as long as “they embrace American values and they place our Constitution at the top level, above their religious beliefs.”

His comments prompted Nihad Awad, a co-founder of the Council on Islamic-American Relations, to call for Carson to withdraw from the race, saying he is “unfit to lead.”

In response, Carson started a petition demanding that the IRS revoke the group’s tax-exempt status because federal laws prohibit tax-exempt nonprofits from intervening in political campaigns.

“Under the Obama administration, the IRS has systematically targeted conservative nonprofit groups for politically motivated audits and harassment,” the petition says. “The agency should now properly do its job and punish the real violators of America’s laws and regulations.”

Carson has regularly polled in second place behind Trump and Trump said Wednesday that he will soon have to go after him, though he is reticent to do so.

“You know he’s a good guy, he’s a nice guy, we get along very well,” Trump told ABC.

He said there are “a lot of issues” he would target Carson on – “one of them would be experience. I mean, Ben is a doctor and that’s what he’s been doing.

“The question is, is he capable of negotiating with China and Russia and Iran and all of the things you have to do?” Trump said. “You know there’ll be a lot of things, but I think at this moment I’m not going to go into them but there will be a lot of things.”