Ahmadeinjad's comments were made when the president spoke over the telephone with his Syrian counterpart late on Wednesday.

Last week, Syria -- a key regional ally of Iran -- accused Israel of pushing the Middle East toward a new war.

Lebanese Prime Minister Saad al-Hariri, in an interview broadcast on Wednesday, said Israeli aircraft were making daily incursions into Lebanese air space, creating a very dangerous situation.

"We have reliable information ... that the Zionist regime is after finding a way to compensate for its ridiculous defeats from the people of Gaza and Lebanon's Hezbollah," Ahmadinejad told Syria's Bashar al-Assad, referring to conflicts in 2006 and 2009.

"If the Zionist regime should repeat its mistakes and initiate a military operation, then it must be resisted with full force to put an end to it once and for all."

Ahmadinejad, who has often predicted the imminent demise of the Jewish state, said Iran would remain on the side of regional nations including Syria, Lebanon and Palestine.

The Islamic Republic does not recognize Israel, which it refers to as the Zionist regime. Israel sees Iran's nuclear program as an existential threat and has not ruled out military action if diplomacy fails to resolve the row.

Iran, the world's fifth-largest crude exporter, says it would retaliate for any attack on its nuclear facilities which it says are part of a peaceful energy program but which the West suspects are aimed at making bombs.

In a statement late last month, Israeli Prime Minister Benjamin Netanyahu said Israel was not planning any imminent attack on Lebanon, from where Hezbollah launched some 4,000 rockets at it during the 34-day war in 2006.

Israeli Foreign Minister Avigdor Lieberman, responding to Syria's accusation last week, has said Damascus would be defeated and Assad would lose power in any future conflict. Netanyahu later reassured Syria that Israel sought peace.

 **Reporting by Hossein Jaseb and Hashem Kalantari; writing by Fredrik Dahl; editing by Matthew Jones