Iran making "big miscalculation": Britain

LONDON (Reuters) - British Prime Minister Tony Blair said on Tuesday Iran was making a "big miscalculation" over its defiance of U.N. demands that it halt its nuclear program.

"The comments from Iran are very worrying ... because yet again they are indicating they want to defy the international community," Blair told a news conference.

Iran vowed on Tuesday never to suspend uranium enrichment, despite an agreement by world powers a day earlier to work on a new U.N. resolution.

"I think Iran is making a big miscalculation," Blair said.

Officials from the five permanent U.N. Security Council members -- the United States, France, Russia, China and Britain -- plus Germany, agreed in London to discuss a new resolution, while also saying they were committed to a negotiated outcome.

"People want a political and diplomatic solution," Blair said, when asked if military action was being considered.

The United States, which says "all options" are on the table while insisting it wants a peaceful solution, has ratcheted up pressure by sending a second aircraft carrier to the Gulf.

Blair urged world leaders to remain united over Iran.

"The tougher and clearer and more unified we are the better result we will get and the less the whole issue of military action arises," he said.

"The tougher we are in insisting Iran comply and be prepared to take tough measures on sanctions and diplomatic action ... then the more likely we are to get the result we want. Any sign of weakness is absolutely fatal," he said.

Blair said a tough message in recent months had yielded results.