WASHINGTON (AP) — Warren Buffett is bringing his fight to raise taxes on the super-wealthy to Congress' deficit-reduction supercommittee.

In an exchange of letters between the billionaire investor and a Republican congressman that Buffett sent the committee this week, Buffett is offering to release his federal tax returns — with a condition.

"If you could get other ultra rich Americans to publish their returns along with mine, that would be very useful to the tax dialogue and intelligent reform," Buffett wrote.

The letters, obtained Wednesday by The Associated Press, were among several sent in recent days to the special bipartisan panel created this summer to find ways to reduce the mushrooming national debt by at least $1.2 trillion over the coming decade.

The same law that produced the supercommittee gave Congress' regular committees until Friday to submit their own suggestions for erasing red ink. Some of those that have trickled in so far indicate that rather than offering dramatic new ideas for savings, many lawmakers are championing longtime favorite proposals and urging the panel to avoid cutting certain programs.

In his letter to the panel, Sen. Tom Harkin, D-Iowa, who heads the Senate Health and Education Committee, asked the panel to take "bold and immediate action to create jobs" while embracing deficit reduction that would take effect after the unemployment rate drops. The leaders of the Senate Environment and Public Works Committee, Chairman Barbara Boxer, D-Calif., and Sen. James Inhofe, R-Okla., combined on a letter asking the supercommittee to "not neglect America's transportation needs."

In Buffett's letter sent Tuesday to Rep. Tim Huelskamp, R-Kan., Buffett did reveal new information about his own earnings last year. He wrote that his adjusted gross income, which can exclude some income and expenses, was $62,855,038. His taxable income was $39,814,784.

In a New York Times opinion piece this summer in which he said tax rates on the wealthiest Americans were too low, Buffett disclosed that he paid $6,938,744 in federal taxes last year, or 17.4 percent of his taxable income. Taxable income is lower than adjusted gross income because it subtracts exemptions and itemized deductions such as charitable contributions and state and local taxes.

Buffett's views have become central to the struggle between President Barack Obama and Congress over how to control the federal debt. Obama has used the "Buffett Rule" to describe his fight to clamp taxes on the wealthy that are at least as high as those paid by lower earners, a drive that Republicans oppose.

Last week, Huelskamp, a conservative freshman, wrote Buffett offering to release his own tax returns if Buffett would do the same.

"If your name is lent to a national policy and your story the justification for a major overhaul to the tax code, then the American people have a right to see the evidence guiding that policy," Huelskamp wrote.

Buffett responded that even an anonymous release of the returns of the 400 richest Americans would show how little taxes some are paying and "would be a big step in informing legislators and the public of what needs to be done."

Buffett forwarded both letters to members of the supercommittee this week with a brief note stating in part, "You may find some of the figures helpful in your deliberations."

As for the letters congressional committees are sending the supercommittee, Harkin's suggests saving money by giving brand-name drugmakers fewer years of patent protection against generic competitors and encouraging students to take education loans directly from their colleges — both policies that have been favored by the Obama administration. Harkin wrote that the supercommittee should avoid cuts to programs including job training, Obama's health care overhaul and aid to the disabled.

Sen. Kay Bailey Hutchison, R-Texas, encouraged the committee to pare savings from Social Security by gradually raising the future retirement age from 67 to 69 and, in some years, trimming annual inflation adjustments in benefits by 1 percentage point. Hutchison has been offering that proposal for weeks but it has been opposed by the seniors group AARP.

Senate Armed Services Committee Chairman Carl Levin, D-Mich., said he and the panel's top Republican, Sen. John McCain of Arizona, hope to write a bipartisan letter that other Armed Services members could support.

But the top Republican on the Senate Finance Committee, Sen. Orrin Hatch, R-Utah, said he is trying to unite minority Republicans on that panel behind their own letter.

Senate Finance Committee Chairman Max Baucus, D-Mont., who is also on the supercommittee, is considered unlikely to send a recommendation letter, as is another supercommittee member, House Ways and Means Committee Chairman Dave Camp, R-Mich.

The supercommittee has until Nov. 23 to send a package of savings to Congress. Lawmakers will have until Dec. 23 to vote on the measure, with failure meaning $1.2 trillion in cuts in defense and many domestic programs will begin taking effect in 2013.