WASHINGTON (Reuters) - Revolution in Iran appears to be a matter of time, US Defence Secretary Leon Panetta predicted on Tuesday, saying the Iranian reform movement was learning from revolts in Tunisia, Egypt, Libya and Syria. Panetta, a former CIA director who took over the Pentagon's top job in July, was asked on the Charlie Rose television show whether the Arab Spring might spread to non-Arab Iran. Panetta responded: "Absolutely." "I think we saw in evidence of that in the last election in Iran that there was a movement within Iran that raised those very same concerns that we're seeing elsewhere," Panetta said. "And I think in many ways, it's a matter of time before that kind of change and reform and revolution occurs in Iran as well." Iranian security forces crushed mass protests in the wake of Iran's disputed June 2009 re-election of President Mahmoud Ahmadinejad. Panetta acknowledged the difficulties supporting such protests given the potential for backlash. "We should try to take every step to try to support their effort but at the same time, we've got to analyse each situation to make sure that we do nothing that creates a backlash or that undermines those efforts," he said. "I think the reform movement in Iran is learning one hell of a lot from what's happened in Tunisia and Egypt and Libya and Syria," Panetta said. Supporters of Iran's opposition Green movement are watching the Arab uprisings with a mixture of admiration, regret for their own movement's failure and concern about what might replace fallen regimes. Meanwhile, Leon Panetta said that Al-Qaeda has been severely weakened in the decade since the 9/11 attacks while the US has demonstrated a spirit of resilience.