New York: US President George W Bush has accepted that his calculations regarding the Iraq war went wrong, but claimed the campaign was a "catastrophic success" despite the escalating violence in the war-torn nation.

Bush, who is under immense domestic pressure over his failure to find the weapons of mass destruction in Iraq, said the "war on terror" was a long-lasting ideological struggle against a totalitarian point of view that advocates terrorism as a tool to intimidate free people.

"Had we had to do it over again, we would look at the consequences of a catastrophic success, being so successful so fast that an enemy that should have surrendered or been done in escaped and lived to fight another day," he told the Time Magazine in an interview. He was referring to his action in Iraq to oust President Saddam Hussein.

He said it was not a failure of imagination that everybody thought Saddam Hussein has weapons of mass destruction.

"I have made it very clear that we thought we would find stockpiles. I remind the people that he had the capability of making those weapons. And therefore that was not a failure of imagination to think that," he said.

Bush, who is seeking re-election, said it was really hard to put people into combat as the consequences of war are death. "I realize that the decisions I have made have put people in harm's way. It's just a hard part of the job, even when you know you're right. It hits you all the time."