NEW YORK (Reuters) - Former Iraqi President Saddam Hussein kept up the illusion that he had weapons of mass destruction before 2003 because he did not think the United States would invade, an FBI agent who questioned him said.

Ousted Iraqi President Saddam Hussein reacts in court during the Anfal genocide trial in Baghdad, December 21, 2006. Saddam kept up the illusion that he had weapons of mass destruction before 2003 because he did not think the United States would invade, an FBI agent who questioned him said. REUTERS/Nikola Solic

In an interview with CBS’ “60 Minutes” to be broadcast on Sunday, FBI agent George Piro describes conversations with Saddam in the months after his capture in December 2003.

Piro said Saddam, who was hanged from crimes against humanity in December 2006, wanted to maintain the image of a strong Iraq to deter Iran, its historic enemy, from hostile action.

“He told me he initially miscalculated ... President (George W.) Bush’s intentions. He thought the United States would retaliate with the same type of attack as we did in 1998... a four-day aerial attack,” Piro said.

“He survived that one and he was willing to accept that type of attack,” Piro said, according to excerpts of the interview released on Thursday.

CBS correspondent Scott Pelley asks Piro: “He didn’t believe the U.S. would invade?” Piro answers: “No, not initially.”

No Iraqi weapons of mass destruction were found despite the Bush administration’s warnings before the March 2003 invasion that Iraq’s arsenal of banned weapons presented a threat to its neighbors and U.S. interests.

Once the invasion was certain, Saddam asked his generals if they could hold the invaders for two weeks, Piro said.

“And at that point, it would go into what he called the secret war,” Piro said, though he added he wasn’t convinced that the insurgency was Saddam’s plan. “Well, he would like to take credit for the insurgency,” said Piro.

CBS said Piro debriefed Saddam for almost seven months, trying to win his confidence by convincing him he was an important envoy answering to Bush.

“This and being Saddam’s sole provider of items like writing materials and toiletries made the toppled Iraqi president open up to Piro, a Lebanese-American and one of the few FBI agents who spoke Arabic,” CBS said.

Even when it became clear that Saddam did not have weapons of mass destruction, he tried to keep up the mystery.

“For him, it was critical that he was seen as still the strong, defiant Saddam. He thought that would prevent the Iranians from re-invading Iraq,” Piro said.

The Iraqi leader had also intended to restart the weapons program and had the means to do it.

“He still had the engineers. The folks that he needed to reconstitute his program are still there,” Piro said. “He wanted ... to reconstitute his entire WMD program.”