Arab states have pledged to step up pressure on Israel to join a global anti-nuclear arms pact, defying US warnings their action could harm Middle East peace talks.

Signalling they were in no mood to compromise, Arab member nations of the International Atomic Energy Agency (IAEA) also sharply criticised a report by its head on Israeli Nuclear Capabilities, saying it was "weak" and "devoid of substance".

The United States and its Western allies urged the group to withdraw a planned resolution at the IAEA's annual assembly next week calling on Israel to sign the Non-Proliferation Treaty and put all of its atomic sites under the UN body's watch.   

Israel, widely assumed to have the Middle East's only atomic arsenal, and the United States see Iran as the region's main proliferation threat, accusing it of seeking to develop atomic weapons. Tehran rejects the charge.

Israel's envoy to the IAEA said the Arab push was politically motivated and it was a "sovereign right" to decide whether or not to accede to the treaty, diplomats at a closed-door meeting of the agency's board said.   

Arab states won narrow backing for a similar resolution at the 2009 general conference of the 151-nation IAEA, but the United States has lobbied hard to avoid a repeat this year.

The US envoy to the IAEA said the non-binding resolution targeting Israel would undermine broader efforts in 2012 towards establishing a region free of weapons of mass destruction, and could also upset Israeli-Palestinian peace negotiations.

"It would do nothing but send a negative signal to the larger peace process," Ambassador Glyn Davies told reporters on the sidelines of the meeting of the IAEA's 35-nation board.

Israel has neither confirmed nor denied having nuclear bombs under a policy of ambiguity to deter its many regional foes. It has said last year's resolution was backed by adversaries that question its right to exist, such as Iran. - Reuters