|Barack Obama is set to announce a new defence strategy that would reduce the circumstances in which the US would be prepared to use nuclear weapons.
It would rule out a nuclear response to attacks on the US involving biological, chemical or conventional weapons.
Nor would the US use nuclear arms on non-nuclear states that comply with the nuclear non-proliferation treaty.
Mr Obama said he would make exceptions for states deemed in violation of the treaty, naming Iran and North Korea.
Ahead of the report's release, Mr Obama told the New York Times he was convinced Iran was on a course that "would provide them with nuclear weapons capabilities".
Last week, Mr Obama said he wanted to see new UN sanctions on Tehran "within weeks".
Tehran insists its nuclear programme is peaceful, but its refusal to adhere to international demands has raised fears of a possible strike on its nuclear facilities by the US or Israel.
The New York Times said Mr Obama described his new policy as "part of a broader effort to edge the world toward making nuclear weapons obsolete, and to create incentives for countries to give up any nuclear ambitions".