Muslim countries have long called for Israel, which is widely believed to have nuclear arms, to open its program.

But the fact that the Arab League has directly approached Washington and other Israeli allies for support at the September meeting of the International Atomic Energy Agency (IAEA) is significant, considering that President Barack Obama last month warned against using that forum to single out Israel.

Obama then suggested that such a move would likely kill hopes of breakthrough talks on a Mideast nuclear-free zone, as proposed by the UN's 189-nation Nuclear Nonproliferation Treaty conference three months ago.

Over Israeli objections, the planned 2012 talks were backed by the US and other nuclear powers for the first time since Arab states pushed for such a gathering 15 years ago.

The Arab appeal to pressure Israel to open its nuclear program to inspectors also threatens to deflect attention from Iran, which Washington and its allies now consider a grave nuclear proliferation threat, even though Tehran insists it is not developing nuclear weapons.

The Arab appeal is contained in a letter signed by Arab League Secretary-General Amr Moussa that was shared with The Associated Press. It asks for backing of a resolution that Arab countries will submit to the September assembly of the IAEA.

An attached draft of the resolution expresses concern about Israel's nuclear program and urges it to join the Nuclear Nonproliferation Treaty and to open its atomic activities to outside inspection.

A cover note asks the Belgian Embassy in Cairo to transmit the letter and the draft to Belgian Foreign Minister Steven Vanackere, who now holds the rotating European Union presidency.

Diplomats accredited to the Vienna-based IAEA and familiar with the issue told the AP that the letter also was sent to US Secretary of State Hillary Clinton and the foreign ministers of Russia, China, Britain and France — the four other permanent UN Security Council members.

Obama and Israeli Prime Minister Benjamin Netanyahu agreed in a statement last month to “work together to oppose efforts to single out Israel” at the 150-nation IAEA conference.

But the Arab letter says the notion of singling out Israel “is not the case.” “Singling out a state assumes that there are a number of states in the same position and only one state was singled out. The fact is that all the states in the region have acceded to the NPT except Israel.”