VIENNA, Austria — A meeting of the U.N. nuclear watchdog’s 145 member nations this week could turn into a showdown between the West and the developing world, as Iran and Syria bid for more influence within the agency, and Islamic nations express anger over Israel’s nuclear program.

The International Atomic Energy Agency’s general conference, starting tomorrow, has traditionally been an annual chance for member countries to plan general nuclear policies that range from strengthening nonproliferation to programs of medical and scientific benefit.

Decisions are usually made by consensus, which in the past has led all sides to bridge sometimes substantial differences to reach compromise. A votes on any topic have been rare in the meeting’s 52-year history, and are considered dents in the meeting’s credibility.

But Islamic nations have grown frustrated with Israel’s refusal to put its nuclear program under international purview, and could force a vote for a third year running. They have lost the vote on Israel in the last two years, and now are threatening to up the ante if they don’t get conference backing on the issue by calling for a vote on every item of this year’s agenda, no matter how minor.

“In all my years of dealing with the general conference, I have never seen it as divided as this,” one conference veteran said today. The diplomat demanded anonymity because he wasn’t authorized to comment to the media.

As in the past two years, Islamic IAEA members are expected to put forward a resolution urging all Middle East nations to refrain from testing or developing nuclear arms and urging nuclear weapons states “to refrain from any action” hindering a Mideast nuclear-free zone.

Israel — widely considered the only Middle East nuclear weapons state — last year called for a vote on that resolution because of the introduction of a separate Arab-backed item deeming Israel a “nuclear threat.” The resolution was defeated, but the fact that it was put to a ballot weakened the consensus principle.

Arab members — backed by Iran — have again asked conference organizers to include a similar item. While it now refers to “Israeli nuclear capabilities” instead of “nuclear threat,” the Jewish State still objects to being singled out — and diplomats told The Associated Press it would again force a vote on the Middle East nuclear-free zone resolution unless the second item is withdrawn.

Focusing on Israel by name “is substantially unwarranted and flawed,” said a letter prepared for review by the conference from the Jewish State’s IAEA representative, Israel Michaeli.

Sponsors of the item should instead “address the most pressing proliferation concerns in the Middle East,” said the letter in allusion to Iran’s defiance of U.N. Security Council sanctions for refusal to stop uranium enrichment and world concerns about allegations that Tehran had past plans to make nuclear weapons.

Yesterday, the U.N. Security Council approved a fourth resolution critical of Tehran’s defiance on uranium enrichment — which can create both nuclear fuel and the fissile core of warheads.

But Iran as well as ally Syria figure even more directly at the Vienna conference because they are among four nations seeking their geographic region’s nomination for a seat on the IAEA’s 35-nation decision-making board.

Iran’s bid is strategic. Tehran is running to counteract an American push to have Afghanistan or outsider Kazakhstan elected over Syria, which is under IAEA investigation for allegedly hiding a secret nuclear program, including a nearly completed plutonium producing reactor destroyed last year by Israel.

Tehran is ready to withdraw from the race if Afghanistan does so, narrowing the field to favored Syria and Kazakhstan, diplomats told the AP. But as of today, Afghanistan, backed by America and its allies, was not ready to do so.

If the regional group does not agree on a candidate by the time the conference turns to the issue, the meeting will also be asked to vote on which nation should take the board seat.