Israel believes Iran will not be able to produce a nuclear bomb before 2015 and a top Israeli official has counseled against pre-emptive military strikes, according to intelligence assessments.

Given in a briefing by Mossad director Meir Dagan upon his retirement, the assessments pointed to new Israeli confidence in U.S.-led sanctions and covert action designed to discourage or delay Tehran's uranium enrichment program.

They were also in line with Israeli Prime Minister Benjamin Netanyahu's public circumspection -- echoing louder misgivings voiced by the Obama administration - about resorting to force against Iran, which denies seeking nuclear arms and has vowed to retaliate against Israel and U.S. interests for any such attack.

"Iran will not achieve a nuclear bomb before 2015," Dagan said, Reuters reported.