NEW YORK (CNN/Money) - The AARP signaled for the first time how vehemently it would fight President Bush's proposal for private Social Security accounts, saying it would launch a $5 million, two-week advertising campaign against the plan timed to coincide with the start of the new Congress, a newspaper report said Thursday.

The influential lobbying group that represents 36 million Americans aged 50 years and older said it would spend much more in the next two years to block the creation of private accounts financed with payroll tax revenues, reported the New York Times.

"This is our signature issue," Christine M. Donohoo, chief communications officer for the AARP, told the paper. "We will do what it takes."

According to the Times, full-page ads are to appear next week in more than 50 newspapers nationwide that read, "There are places in your retirement planning for risk, but Social Security isn't one of them."

The report says another advertisement shows a picture of traders standing on an exchange floor. "Winners and losers are stock market terms," it reads. "Do you really want them to become retirement terms?"

Earlier this month, President Bush said with regards to Social Security, "The crisis is now."

But Donohoo disagreed, telling the Times that "rather modest changes" could ensure the solvency of the system for several generations. "We're not in a crisis," she said.