AFP - Prime Minister Gordon Brown described the United States as Britain's "most important ally" and praised closer ties between France, Germany and the US in an interview broadcast Sunday.

LONDON (AFP) — Prime Minister Gordon Brown described the United States as Britain's "most important ally" and praised closer ties between France, Germany and the US in an interview broadcast Sunday.

Brown, who has stepped back from the shoulder-to-shoulder relations between US President George W. Bush and former premier Tony Blair since taking office in June, added he would not rule out a nuclear strike on Iran if diplomacy failed.

Brown has appointed a number of critics of the US to his cabinet, including former UN deputy chief Mark Malloch Brown, while his interactions with Bush seemed more formal than Blair's on a trip to meet the president in July.

Analysts and commentators also detected cracks in the "special relationship" between the two nations over the withdrawal of some British troops from southern Iraq in September.

But Brown took a warmer line in an interview with Sky News television, saying that Britain was "part of an international endeavour" over efforts to curb Iran's nuclear ambitions.

"America is our most important ally. It will always be because of the values we share with America absolutely essential to how we conduct our foreign policy," he said.

"The great change that is taking place that I think is to the advantage of everyone is that France and Germany and the European Union are also moving more closely with America and I think that's to the benefit of Britain, it's to the benefit of the world."

He added: "While nothing should be ruled out, it is important to say that the sanctions that we are placing on Iran are having some effect."

Brown also said the relationship with the US was important in efforts to reform international institutions and tackle issues including climate change, security and global economic competition.

"Over the next few years, as European countries like France and Germany move closer to America as we've seen over these last few weeks and months, there's a great opportunity for all of us to work together to reshape the international institutions," he said.

Asked whether such efforts would have to wait until Bush left office, he replied: "Not at all".