WASHINGTON  President Obama mounted a frontal assault on the insurance industry on Saturday, accusing it of using “deceptive and dishonest ads” to derail his health care legislation and threatening to strip the industry of its longstanding exemption from federal antitrust laws.

In unusually harsh terms, Mr. Obama cast insurance companies as obstacles to change interested only in preserving their own “profits and bonuses” and willing to “bend the truth or break it” to stop his drive to remake the nation’s health care system. The president used his weekly radio and Internet address to challenge industry assertions that legislation will drive up premiums.

“It’s smoke and mirrors,” Mr. Obama said. “It’s bogus. And it’s all too familiar. Every time we get close to passing reform, the insurance companies produce these phony studies as a prescription and say, ‘Take one of these, and call us in a decade.’ Well, not this time.”

Rather than trying to curb costs and help patients, he said, the industry is busy “figuring out how to avoid covering people.”