WASHINGTON — Sen. John McCain, R-Ariz., on Monday defended his statement over the weekend that illegal immigrants were responsible for some Arizona wildfires, citing congressional testimony and published reports to back his claim.

Speaking from his home state Saturday, McCain said there was “substantial evidence that some of these fires have been caused by people who have crossed our border illegally.” He didn’t specify what evidence, however.

The comment drew criticism, including from an unsuccessful candidate in Arizona’s Democratic Senate primary in 2010, who accused McCain of fanning “the flames of intolerance.”

Speaking on the “Imus in the Morning” show Monday, McCain stood by his statement.

“I was briefed by the Forest Service about the fact that illegal immigrants sometimes start these fires,” he said. And there has been testimony by service officials that “large numbers of warming and cooking fires built and abandoned by cross-border violators have caused wildfires that have destroyed cultural and natural resources.”

He also cited a Los Angeles Times report backing his claim, though it was unclear which story he was referring to.

Imus challenged McCain, though, saying the reports don’t prove illegal immigrants were responsible for the so-called Wallow blaze raging through eastern parts of the state.

McCain said he never was referring to the specific fire in his remarks.

“I’m surprised that anyone should be surprised that people have been doing this for some period of time,” McCain said.

The Wallow fire is burning far north of the U.S.-Mexico border, though there are others nearer, according to InciWeb.

Through Sunday evening the Wallow fire spanned more than 519,000 acres, spilling across into New Mexico.