Paris ? Forty-three nations, including Israel and Arab states, pledged Sunday to work for a Middle East free of weapons of mass destruction at the close of a summit to launch an unprecedented Union for the Mediterranean aimed at securing peace across the restive region.

In a final declaration, Israel, Syria and the Palestinians – along with countries across Europe, the Middle East and North Africa – agreed to “pursue a mutually and effectively verifiable Middle East Zone free of weapons of mass destruction.”

The countries committed to “consider practical steps to prevent the proliferation” of nuclear, chemical and biological weapons and their delivery systems. It was unclear, however, how the signatories – who included Israeli Prime Minister Ehud Olmert and Syrian President Bashar Assad – would enforce the pledge.

Israel is widely believed to have a stockpile of nuclear weapons but neither confirms nor denies it has them – an ambiguity meant to scare potential enemies from considering an annihilating attack while denying them the rationale for developing their own nuclear deterrent.

Recently, tensions between Israel and archenemy Iran have risen over Tehran’s nuclear program. Iranian President Mahmoud Ahma-dinejad has often spoken of wiping Israel off the map. And Israel and ally the United States believe Tehran’s nuclear program is aimed at producing nuclear weapons, despite Iran’s insistence it is for producing nuclear energy.

Syria, another Israeli foe, may also have nuclear ambitions. Last year, Israeli jets destroyed what U.S. intelligence officials said was believed to be a partially built nuclear reactor in Syria, though Syrian officials said it was part of a non-nuclear military program.

While trying to unify the region, the summit laid bare the divisions that still slice through it and highlighted how hard it will be to parlay the meeting’s goodwill and words into progress. Syria’s president refused to shake the Israeli prime minister’s hand, and Morocco’s king snubbed the meeting attended by the president of rival Algeria.