Ben Carson said it was "ridiculous" to blame George W. Bush for the 9/11 terror attacks, but added he doesn't believe that's what Donald Trump meant with his recent controversial comments on the matter.
During a brief campaign stop in Old Town Alexandria, Virginia, Friday night, Carson gave Trump the benefit of the doubt over his comments, made to Bloomberg TV, on Bush: "He was president, OK? Don't blame him or don't blame him, but he was president. The World Trade Center came down during his reign."
"Did he say that he was blaming him for it?" Carson said. He added he'd be "surprised" if Trump meant such a thing, and that "I think it's ridiculous to suggest [Bush] was responsible for that."
Carson also weighed in on his spat with CNBC over debate parameters and President Barack Obama's announcement on troop levels in Afghanistan.
On the debates, Carson said "three hours is just too long," and dismissed critics who suggested both he and Trump were trying to avoid foreign policy questions.
"They can speculate all they want, it's just too long," he said.
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Carson seemed not to be aware of plans to draw down troop levels in Afghanistan in 2017, and suggested 10,000 that are currently there — the number is just under that, and is supposed to drop to 5,500 around the start of 2017 — should stay.
"We need to work in conjunction with our intelligence there. It appears that they're in agreement with a level of around 10,000," Carson said. "They need that in order for there to be a base for their operations there, so unless there's a good reason to change that I don't see a need for an immediate change."
Carson also calling for unity and warning of "global jihadists" who want to "destroy America."
"If we fight each other, all we're doing is helping them," he said.
Carson greeted about 150 excited fans who came out to the town square to see him, before taking a walk to a fundraiser at a restaurant down the street.
Carson was greeted by Debbie Rumpf and her young son, a former patient of Carson's. A group of 8th-grade students visiting on a class trip from Indiana excitedly jostled to snap a selfie with him.
"I got a selfie with a future president!" one student exclaimed, as Carson began his parade down the street.
Carson heads to Texas for more book tour stops Saturday, and will appear on ABC's "This Week" on Sunday.
This article originally appeared on NBCNews.com.