The report was published Tuesday by the Institute for Science and International Security.
It says the main priority is to prevent Iran from achieving "critical capability" through non-military means and that doing so will require a broad range of responses.
One is to increase the number of inspections of Iranian nuclear facilities by the International Atomic Energy Agency to at least two a week, the report says.
Denial of access to IAEA inspectors could lead to a military response to prevent Iran from making enough uranium for a bomb, the report states.
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