Sen. John McCain (R-AZ) is not backing down from his suggestion that illegal immigrants were responsible for some of the massive wildfires in Arizona.

"I was briefed by the Forest Service about the fact that illegal immigrants sometimes start these fires," McCain told Fox Business Network's Don Imus Monday. "I'm surprised that anyone should be surprised that people have been doing this for some period of time."

The Arizona senator was responding to the controversy generated by remarks he made at a press conference Saturday.

“We are concerned about, particularly, areas down on the border where there is substantial evidence that some of these fires are caused by people who have crossed our border illegally,” McCain said. “They have set fires because the want to signal others. They have set fires to keep warm and they have set fires in order to divert law enforcement agents and agencies from them.”

Watch this video from Fox Business Network's Imus in the Morning, broadcast June 20, 2011.