Los Angeles ? While the White House and the Republican National Committee have taken an official “no comment” approach to Michael Moore and his new anti-Bush documentary “Fahrenheit 9/11,” some conservatives have mobilized a letter-writing campaign and crafted ads that slam the film and its maker.

“Fahrenheit 9/11,” which won the top prize at the Cannes Film Festival, attacks President Bush’s rationale for the war in Iraq and accuses him and his administration of manipulating the Sept. 11 terror attacks and fostering fear for political gain.

It is set for release on June 25, debuting on at least 500 screens, with plans to expand to hundreds more in the coming weeks.

One of the organizations rallying against Moore is Move America Forward, a pro-Bush group that evolved months ago from the letter-writing campaign that led CBS to drop its controversial TV movie “The Reagans.”

The group has received several thousand e-mails of support for its Moore campaign, said executive director Siobhan Guiney, a former Republican lobbyist. But she did not know how many were sent to the various theater chains.

“Since we are the customers of the American movie theatres, it is important for us to speak up loudly and tell the industry executives that we don’t want this misleading and grotesque movie being shown at our local cinema,” the group says on its Web site, above a listing of phone numbers and e-mails for various cinema companies.

Said Guiney: “(Moore) is critical of what’s happening right now, and there’s no problem with being critical — but his movie is not a documentary, it’s a piece of propaganda.”

So far, however, Move America Forward’s letters about “Fahrenheit 9/11” haven’t changed anything.

“There has been some communication, but not an overwhelming amount. And we do intend to play the film,” said Dick Westerling, spokesman for the theater chain Regal Entertainment Group, which has 6,020 screens in the United States.