WASHINGTON  Before invading Iraq in 2003, the Bush administration mounted a significant diplomatic offensive to rally international support, and officials at the White House, Pentagon and State Department went to great lengths to trumpet those nations that joined what they termed “the coalition of the willing.”

But historians researching those early alliance-building efforts say they are troubled by what seem to be deletions of and alterations to the early official lists of nations that supported the war effort. The lists were posted on the White House Web site.

While administration officials acknowledged that the number of nations supporting the war changed over time, academic researchers say three official lists appear to have been changed, yet retained their original release date, making them appear to be unaltered originals.

Two other White House lists appear to have been taken off the Web site, according to a study of the documents by Scott L. Althaus and Kalev H. Leetaru of the Cline Center for Democracy at the University of Illinois at Urbana-Champaign.