“There were plenty of warnings about 9/11. Plenty of them. Bush saw them, Condi Rice saw them, they neglected them because their minds were on bigger things,” Oliver Stone exclaimed recently at Deadline’s Toronto International Film Festival studio.

As we mourn today the tragedies that occurred 15 years ago at the Twin Towers, the Pentagon, and aboard United Airlines flight 93, Stone says what upsets him the most as he looks back is that we could have avoided 9/11 had the U.S. government responded promptly to what several agencies knew.

“They did a terrible job,” criticizes the three-time Oscar-winning filmmaker in the above video.

Five years after 9/11, Stone made the movie World Trade Center about the two Port Authority police officers who were trapped under the rubble and survived.  They were two of 20 who walked away from Ground Zero.

“That was the most realistic portrait I could give you of 9/11,” Stone says, explaining he wanted to avoid all the hype, politics and commissions. “The truth is it was a horror show from beginning to end.” (Stone points out that Edward Snowden enlisted because of 9/11.) “At that time, the NSA, the CIA, and the FBI did not do a good job.”

The director continues that a massive bureaucracy was already in place prior to 9/11 which still failed to “connect the dots because the information would come in from different agencies.”

“This thing was covered up,” says Stone about 9/11, “There seems to be a reluctance on the part of the Bush Administration to really fight this thing, to really do something about it. In a sense you might think that they let it happen because it helped their agenda, which they put through with the Patriot Act and many other things, the war in Iraq.”

Stone’s latest movie Snowden opens on Sept. 16 from Open Road Films.