WASHINGTON, Sept. 3 — A previously undisclosed exchange of letters shows that President Bush was told in advance by his top Iraq envoy in May 2003 of a plan to “dissolve Saddam’s military and intelligence structures,” a plan that the envoy, L. Paul Bremer, said referred to dismantling the Iraqi Army.

Mr. Bremer provided the letters to The New York Times on Monday after reading that Mr. Bush was quoted in a new book as saying that American policy had been “to keep the army intact” but that it “didn’t happen.”

The dismantling of the Iraqi Army in the aftermath of the American invasion is now widely regarded as a mistake that stoked rebellion among hundreds of thousands of former Iraqi soldiers and made it more difficult to reduce sectarian bloodshed and attacks by insurgents. In releasing the letters, Mr. Bremer said he wanted to refute the suggestion in Mr. Bush’s comment that Mr. Bremer had acted to disband the army without the knowledge and concurrence of the White House.

“We must make it clear to everyone that we mean business: that Saddam and the Baathists are finished,” Mr. Bremer wrote in a letter that was drafted on May 20, 2003, and sent to the president on May 22 through Donald H. Rumsfeld, then secretary of defense.