US President Barack Obama warned Tuesday that attempts to single out Israel over its undeclared nuclear program could scupper a Middle East regional nuclear conference planned for 2012.

Obama delivered the warning in a statement about his talks with Israeli Prime Minister Benjamin Netanyahu, in which he gave Israel a veiled, but public assurance over its strategic nuclear ambiguity.

"The President emphasized that the conference will only take place if all countries feel confident that they can attend, and that any efforts to single out Israel will make the prospects of convening such a conference unlikely," the statement said.

Obama also agreed to work with Israel to oppose any efforts to single out the Jewish state at the International Atomic Energy Agency (IAEA) General Conference in September.

After a decade of deadlock, the Non-Proliferation Treaty's 189 nations proposed new steps in May towards nuclear disarmament and making the Middle East free of atomic weapons.

Diplomats at an NPT review conference approved by consensus a 28-page final document that for the first time laid out action plans on disarmament, non-proliferation and promoting peaceful atomic energy.

The wording on the Middle East called for holding a conference in 2012 "to be attended by all states of the Middle East, leading to the establishment� of such a nuclear-weapon-free zone.

The NPT review conference called on Israel to join the treaty, which would oblige the Jewish state to do away with its nuclear weapons.

After his Oval Office talks, Obama told reporters that he had "reiterated" to Netanyahu that there was "no change in US policy" on nuclear proliferation in the Middle East.

"We strongly believe that, given its size, its history, the region that it's in, and the threats that are leveled against us -- against it, that Israel has unique security requirements.

"It's got to be able to respond to threats or any combination of threats in the region. And that's why we remain unwavering in our commitment to Israel's security.

"And the United States will never ask Israel to take any steps that would undermine their security interests."

Netanyahu thanked Obama for "reaffirming to me in private and now in public as you did the longstanding US commitments to Israel on matters of vital strategic importance."

Israel, which opposes creating a nuclear free zone until Middle East peace has been achieved, has never acknowledged that it has nuclear weapons.

It is widely believed to be the only nuclear power in the Middle East, with around 200 warheads, but has maintained a policy of deliberate ambiguity about its capabilities since the mid-1960s.