Israel believes Iran would not be capable of producing a nuclear bomb before 2015 and a top Israeli official has counselled against pre-emptive military strikes, intelligence assessments published on Friday said.

The briefings, given by Mossad spy service director Meir Dagan upon his retirement on Thursday, suggested new Israeli confidence in US-led sanctions and covert action designed to discourage or delay Tehran's uranium enrichment programme.

'Iran will not achieve a nuclear bomb before 2015, if that,' Dagan said, according to a transcript obtained by Reuters.

In June 2009, Dagan told an Israeli parliamentary panel that Iran could have its first nuclear warhead by 2014.

Dagan, an ex-general whose eight-year Mossad tenure was widely seen as having escalated Israel's shadow wars against enemies abroad, was circumspect on the prospect of using open force against Iranian nuclear sites.

Such attacks could prompt Iran, which denies seeking the bomb, to quit the nuclear Non-Proliferation Treaty and pursue its programme entirely free of UN inspections, Dagan said.

'Israel should not hasten to attack Iran, doing so only when the sword is upon its neck,' Dagan said.

Israel is widely assumed to have the region's only nuclear arsenal but many analysts say its air force is too small to take on Iran's distant, dispersed and fortified facilities alone.

Israel also is mindful of the risk of retaliatory strikes from Iran. The US has said it does not want to see a new regional war, though, like Israel, it has not ruled out force against Iran.-Reuters