John McCain (R-AZ) says undocumented immigrants are to blame for the massive wildfires that have ravaged Arizona.

"There is substantial evidence that some of these fires are caused by people who have crossed our border illegally," McCain, said at a press conference Saturday after touring the Wallow fire, which began on May 29 and has burned over 500,000 acres to date.

“They have set fires because they 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,” McCain said. “The answer to that part of the problem is to get a secure border."

McCain did not provide any evidence to support his claim, however.

On Sunday, Tom Berglund, a U.S. Forest Service spokesman, told ABC News that there is no evidence that undocumented immigrants had caused the Wallow fire. "Absolutely not, at this level,” Berglund said. "There's no evidence that I'm aware, no evidence that's been public, indicating such a thing.”

Berglund did say, however, that the cause of the Wallow fire, now the largest wildfire in Arizona history, had been determined to be human -- specifically an “escaped campfire.” Two persons of interest were questioned, but no arrests were made.

Latino groups sharply criticized McCain for his remarks. "With the lack of evidence, he might as well also blame aliens from outer space for the fires,” Angelo Falcon, the president of the National Institute for Latino Policy, told CNN. Randy Parraz, whose organization Citizens for a Better Arizona is trying to recall the state senator who sponsored Arizona's controversial anti-illegal immigration law, called McCain's remarks “careless and reckless.”

"It's easier to fan the flames of intolerance, especially in Arizona," he said.

UPDATE:

On Monday, McCain's office released a statement clarifying the senator's remarks, saying that while he had toured the Wallow fire on Saturday, his comments were referring to blazes in southern Arizona more generally, both now and in years past.

“The facts are clear. For years, federal, state and local officials have stated that smugglers and illegal immigrants have caused fires on our southern border," said Brooke Buchanan, Senator McCain's communications director. "During the press conference on Saturday, Senator McCain was referring to fires on the Arizona/Mexico border, not the Wallow Fire.”

Watch McCain's remarks above.