In an interview with Kol Hai Radio, Peres also said that the arrest before the weekend of a Hizbullah terror cell in Egypt was a blow to Iranian President Mahmoud Ahmadinejad's power.
"Ahmadinejad recruits forces against us, but there are also forces against him," Peres said. "What happened in Egypt created a fierce opposition and we must unify all his opponents - the Sunnis and the Europeans, as well as those afraid of nuclear weapons and terror."
Peres went on to say that he hoped Obama's call for dialogue with Ahmadinejad would be heeded, but warned that if such talks don't soften the Iranian president's approach "we'll strike him."
"We certainly cannot go it alone, without the US, and we definitely can't go against the US. This would be unnecessary," stressed the president.
Peres also referred to the case of Israeli spy Jonathan Pollard, imprisoned in the US, saying that even if Israel had done more, it wouldn't have secured his release as "until now, all our appeals to America have been answered with an iron wall."