Details of UN disagreements between Obama, Brown and Sarkozy explains why the Frenchman mocked US President for the naivety of his "dreams"
The President is believed to have angered the European leaders by insisting on delaying a joint press conference until after he had chaired a meeting of the UN Security Council.
Mr Obama is said to have been worried the announcement would undermine the impact of his session on nuclear non-proliferation.
Details of the disagreement appeared to explain why Mr Brown and Mr Sarkozy, the French president, took a harder line on Iran than the American leader at the meeting
The Prime Minister said it was time "to draw a line in the sand" on Tehran's nuclear programme while the Frenchman mocked Mr Obama for the naivety of his "dreams" of eliminating nuclear weapons.
According to French officials, Mr Brown and particularly Mr Sarkozy wanted to make a declaration on Sep 24, either at the Security Council meeting chaired by the US president or just afterwards.
The Europeans considered that there was no better stage from which to tell the world that the three countries' intelligence services had worked together to uncover an underground uranium enrichment facility under construction at Qom.
But Mr Obama did not want to "spoil the image of success" of his disarmament session, (continues here)