TEHRAN, Iran - U.S. diplomatic cables released by WikiLeaks show that Iran's hard-line policies have left it without "a single ally" among neighboring countries, an Iranian opposition figure said Sunday in a challenge to the official view that the disclosures were only a ploy by Washington to poison Iran's relations in the region.

The claim by Mir Hossein Mousavi highlights the difficult position of Iran's ruling establishment following release of the memos, which show some Arab leaders - including Saudi Arabia's powerful King Abdullah - urging U.S. military action to halt Iran's nuclear program.

Iran claims the cables are an effort by Washington to try to mobilize support for a possible military strike.

But U.S.-allied Gulf Arab leaders have made no attempts to backtrack in public from their private statements. Last week, at a summit in Abu Dhabi, they sharply warned Iran to stay out of their affairs.

A strong stance by the Gulf Arab states could pose further economic hardships for Iran because of close trade ties and make it harder for Tehran to claim that only the West is demanding answers about its nuclear program.

Mousavi, in a statement posted on his website, said the WikiLeaks releases "clearly show our vulnerable situation in the region."

He blamed the hard-line stance of President Mahmoud Ahmadinejad for Iran's international isolation.

"With such policies, we effectively don't have a single ally among our neighbors," said Mousavi, who claimed widespread vote-rigging after his loss to Ahmadinejad in last year's disputed elections.

The unrest that followed - the worst domestic upheavals since the 1979 Islamic Revolution - led to a relentless crackdown on dissidents.

The U.S. diplomatic messages concerning Iran dwell heavily on trying to decipher Iran's internal tensions and its nuclear ambitions, which the U.S. and its allies worry could eventually lead to atomic weapons. Iran insists it seeks reactors only for energy and research.

Iran first dismissed the State Department memos as "mischief" aimed at damaging Tehran's ties with the Arab world. But then the depth of Arab concern made headlines around the world - including Saudi King Abdullah's urging a U.S.-led attack on Iran to "cut off the head of the snake."