Israeli Prime Minister Binyamin Netanyahu has cancelled his attendance in the nuclear summit in Washington next week, due to fears that Israel would be pressured to sign the international Nuclear Non-Proliferation Treaty (NPT).
The summit, which will include 47 nations, is part of Mr Obama's agenda towards nuclear disarmament and non-proliferation.
Israel was initially due to send a low-level delegation but Mr Netanyahu agreed to take part after he received reassurances from American officials that Israel would not be forced to disclose its nuclear capabilities or commit to reducing them.
Israel has long maintained a policy of 'nuclear ambiguity', in which it neither confirms nor denies whether it has nuclear weapons.
However, in recent days Israel has become increasingly concerned at reports that Egypt, Turkey and other Muslim states were going to demand that Israel sign the NPT, and decided to send Intelligence and Atomic Energy Minister Dan Meridor to the summit instead.
Mr Netanyahu, who clashed with Mr Obama in the White House last month over building in east Jerusalem, was not due to meet privately with Mr Obama at the conference.
The Americans are still waiting for his response to their demands over the peace process, including a freeze of building in east Jerusalem and a commitment to continue the 10-month freeze on building in the West Bank, due to end in September.