In the UN speech, Netanyahu said Iran was proceeding rapidly and could have the infrastructure in place to build a nuclear bomb in a year or so.
In the leaked document, published yesterday by The Guardian and Al-Jazeera, the Mossad purportedly says that Iran "is not performing the activity necessary to produce weapons."
The document's authenticity couldn't be verified. An Israeli official said there was "no discrepancy" between the two assessments. He spoke anonymously as he was not authorized to discuss the issue.