"No one has seen the final version of the film, because the editing process is not yet complete, so criticisms of film specifics are premature and irresponsible," the network said in a statement Thursday.
Former administration officials and Senate Democrats said in letters to the head of the network's parent company that the "The Path to 9/11" was "terribly wrong."
ABC says the movie is a dramatization with fictionalized scenes, CBS News senior White House correspondent Bill Plante reports, but they also say it's drawn from sources, including the 9/11 Commission report.
Not so fast, says 9/11 commissioner Richard Ben-Veniste.
"They are representing to the world that this is the 9/11 Commission's findings and it ought to be accurate, and it wasn't," Ben-Veniste said.
Former President Clinton, speaking with news reporters after a Democratic fundraiser in Arkansas on Thursday, said he hadn't seen the ABC film.
"But I think they ought to tell the truth, particularly if they are going to claim it is based on the 9/11 commission report," he said. "They shouldn't have scenes that are directly contradicted by the findings of the 9/11 report."
Executive producer Marc Platt said editing of the miniseries was going on and "will continue to, if needed until we broadcast," but declined to discuss the specific scenes that were being changed, The New York Times reported Friday.
"From Day 1, we've examined any issue or question that's arisen," Platt said. "And we'll continue to do so until the last possible moment."
The Times, citing Thomas Kean, the chairman of the Sept. 11 commission and a consultant for the miniseries, reported that one scene being changed portrayed Samuel R. Berger, the former national security adviser, hanging up on a CIA officer at a critical moment of a military operation.
Two other scenes under review, according to Kean, portrayed former Secretary of State Madeleine Albright apparently obstructing efforts to capture Osama bin Laden and Mr. Clinton being too distracted by impeachment and his marital problems to focus on bin Laden.
Albright, Berger, Clinton Foundation head Bruce Lindsey and Clinton adviser Douglas Band wrote in the past week to Robert Iger, CEO of ABC's parent, The Walt Disney Co., to express concern over "The Path to 9/11."
They were joined Thursday by Democratic Sens. Harry Reid of Nevada, Dick Durbin of Illinois, Debbie Stabenow of Michigan, Charles Schumer of New York and Byron Dorgan of North Dakota, who sent a joint letter to Iger asking that the broadcast be cancelled.
The two-part miniseries, scheduled to be broadcast on Sunday and Monday, is drawn from interviews and documents including the report of the Sept. 11 commission.
Kean, the former Republican New Jersey governor who led the commission, defended the miniseries.
"It's something the American people should see," he said in an interview on ABC's "Good Morning America" Friday. "Because you understand how these people wanted to do us harm, developed this plot, and how the machinations of the American government under two administrations not only failed to stop them, but even failed to slow them down."
Kean said he hoped people would watch the miniseries to "understand better what went on, and hopefully understand what still needs to be done."
The letter writers said the miniseries contained factual errors and that their requests to see it had gone unanswered. They said people familiar with the movie had told them about it, but they didn't name them.
"By ABC's own standard, ABC has gotten it terribly wrong," Lindsey and Band said in their letter. "It is unconscionable to mislead the American public about one of the most horrendous tragedies our country has ever known."
ABC said that for dramatic and narrative purposes "the movie contains fictionalized scenes, composite and representative characters and dialogue and time compression."
"We hope viewers will watch the entire broadcast of the finished film before forming an opinion about it," ABC said.
In the senators' letter, they questioned the political leanings behind the miniseries.
"Frankly, that ABC and Disney would consider airing a program that could be construed as right-wing political propaganda on such a grave and important event involving the security of our nation is a discredit both to the Disney brand and to the legacy of honesty built at ABC by honorable individuals from David Brinkley to Peter Jennings," the letter said.
The letter writers pointed out examples of scenes they had been told were in the miniseries but that they said never happened. Albright objected to a scene that she was told showed her insisting on warning the Pakistani government before an air strike on Afghanistan, and that showed her as the one who made the warning.
"The scene as explained to me is false and defamatory," she said.
Berger objected to a scene that he was told showed him refusing to authorize an attack on bin Laden despite the request from CIA officials.
"The fabrication of this scene (of such apparent magnitude) cannot be justified under any reasonable definition of dramatic license," he wrote.
The five-hour miniseries is set to run without commercial interruption. Director David Cunningham said it was a massive undertaking, with close to 250 speaking parts, more than 300 sets and a budget of $40 million. Cunningham has said he shot 550 hours of film. The cast includes Harvey Keitel, Patricia Heaton and Donnie Wahlberg.