President Bush vowed Saturday not to let a few bad apples in corporate America "tarnish our entire free enterprise system."

"Despite recent abuses of the public's trust, our economy remains fundamentally sound and strong," Bush said in his weekly radio address. "No violation of the public's trust will be tolerated. The federal government will be vigilant in prosecuting wrongdoers to ensure that investors and workers maintain the highest confidence in American business."

The president's focus on big business accounting scandals, his fourth in as many days, could barely keep up with events.

Bush referred, though not by name, to WorldCom's disclosure earlier this week that it misrepresented $3.8 billion in expenses. By Friday, Xerox had announced it, too, had overstated revenues by billions of dollars.

"Confidence is the cornerstone of our economic system, so a few bad actors can tarnish our entire free enterprise system," Bush said. "America is ushering in a new era of responsibility and that ethic of responsibility must extend to America's boardrooms."

He listed administration efforts against corporate fraud: quick investigations into and actions against companies by the Securities and Exchange Commission and a 10-point plan that includes taking ill-gotten gains back from company executives and denying them the chance to serve on boards of directors.

Bush's address, recorded Friday, was broadcast on the day he was undergoing a colon screening by military doctors at Camp David, Md. Because short-term sedation was involved, Bush was turning over the powers of the presidency during that time to Vice President Dick Cheney.

The Associated Press contributed to this report.