His remarks coincided with the arrival of U.S. President George W. Bush in the Middle East to celebrate Israel's 60th birthday and try to energise peace efforts complicated by a corruption scandal that could topple Prime Minister Ehud Olmert.
Opposition to Israel is a fundamental principle in Shi'ite Muslim Iran, which backs Palestinian militants opposed to peace with the Jewish state.
"The Zionist regime is dying," Ahmadinejad said in a speech in the northern city of Gorgan, referring to Israel. "The criminals imagine that by holding celebrations … they can save the Zionist regime from death."
"They should know that regional nations hate this fake and criminal regime and if the smallest and briefest chance is given to regional nations they will destroy (it)," said Ahmadinejad, who often rails against Israel and the United States.
A 2005 statement by Ahmadinejad saying that "Israel should be wiped off the map" outraged the international community.
Last month, a senior Iranian army commander said Iran will respond to any military attack from Israel by "eliminating" it, in comments condemned by Washington.
Iran, the world's fourth-largest oil producer, says it has developed ballistic missiles able to hit Israel and U.S. bases in the region.
Some analysts have speculated that Israel might attack Iran to stop its nuclear activities, which the West fears are a front for weapons development. Iran, which does not recognise Israel, insists it wants nuclear technology only for electricity.
Washington says it wants a diplomatic resolution to the nuclear dispute but has not ruled out military action if that fails. Tehran insists it will not bow to Western pressure.
(Reporting by Zahra Hosseinian; Writing by Fredrik Dahl; Editing by Samia Nakhoul)
