Reiterating angry comments he made last month after Iranian President Mahmoud Ahmadinejad called for Israel to be "wiped off the map", Blair said there was a "real risk" that Tehran's stance could derail the Non-Proliferation Treaty.

"If Iran was to develop nuclear weapons capability then I think it would pose a very serious threat to world stability and peace," he told a quarterly meeting with parliamentary committee chairmen.

"I don't think there's any doubt about that at all."

Blair described relations with Iran as "increasingly strained" since Ahmadinejad's October 27 statement, which was condemned outright by the European Union and the United States.

Dialogue and working relations were ongoing with Tehran "at some levels", said Blair, who nevertheless added: "Things have definitely got more difficult since the election of the new president."

Blair refused to comment about whether Britain could be dragged into a potential conflict sparked by alleged Iranian incursions into neighboring Iraqi waters.

But suspected nuclear weapons, Tehran's refusal to cooperate with the International Atomic Energy Agency (IAEA), its support of terrorism and "meddling" in Iraq were all areas where Britain had a "real, genuine cause for concern".

Talks will be held early next month between Iran, Britain, France, Germany and Russia about the Islamic republic's disputed nuclear program, diplomats announced Tuesday.

"No one is talking military action or any of the rest of it," Blair told the liaison committee, which is made up of the heads of all the various committees in the lower chamber of Britain's parliament, the House of Commons.

"Iran is a quite different country from Iraq in many, many ways. It may be that the change in Iran comes from within, ultimately," he said.

"But it's a concern and a worry for us because they're a powerful country and have a large part of the world's energy resources at their disposal."

Blair stressed that the "long-term spread" of democracy, human rights and cooperation between countries would help improve security in the Middle East.

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