The United States backs Israel's right to weapons of deterrence, Prime Minister Ariel Sharon (search) said Thursday, an oblique reference to Israel's secret store of nuclear weapons.

Sharon told a political party gathering in Tel Aviv that the United States recognizes that "Israel faces an existential threat, and it must be able to defend itself by itself by preserving its deterrent capability."

Sharon noted that Iran is under U.S. pressure to stop its nuclear weapons program (search), and Libya took steps to halt its nuclear arms development, but "we have received here a clear American position that says in other words that Israel must not be touched when it comes to its deterrent capability."

Israel has never admitted possessing nuclear weapons, maintaining a policy of ambiguity. However, based on pictures and information given to the London Sunday Times in 1987 by nuclear whistleblower Mordechai Vanunu, experts have determined that Israel has dozens, perhaps hundreds, of nuclear bombs.

Sharon said the United States backs "Israel's right to defend itself by itself against threats at any place and to preserve Israel's deterrent power against all threats."

Critics of Israeli and U.S. policy have questioned why the United States has pressed Iraq, Iran, Libya and North Korea to stop developing nuclear weapons, when Israel faces no similar pressure.