The review is due to be completed by the end of this year, and European officials say the outcome is not yet clear. But one official said: "Obama is now driving this process. He is saying these are the president's weapons, and he wants to look again at the doctrine and their role."
The move comes as Obama prepares to take the rare step of chairing a watershed session of the UN security council on Thursday. It is aimed at winning consensus on a new grand bargain: exchanging more radical disarmament by nuclear powers in return for wider global efforts to prevent further proliferation.
That bargain is at the heart of the nuclear non-proliferation treaty, which is up for review next year amid signs it is unravelling in the face of Iranian and North Korean nuclear ambitions.
In an article for the Guardian today, the foreign secretary, David Miliband, argues that failure to win a consensus would be...
