Not the time to rush for more Iran sanctions: UK

LONDON (Reuters) - Major powers should not rush to impose new sanctions on Iran at a time when Tehran has a good chance to move to normal ties with Washington, British Foreign Secretary David Miliband said on Tuesday.

In a sharp change in U.S. policy, President Barack Obama has offered a new start in relations with Iran after decades of deep mistrust between the two countries, which are also locked in a dispute over Iran's nuclear program.

Britain, a close U.S. ally and one of the six powers that have been trying to persuade Iran to abandon uranium enrichment, has backed the new American approach.

Miliband told Britain's parliament that the U.S. offer "represents the best chance Iran will ever have to normalize its relations with the rest of the world and above all to normalize its relations with the U.S."

Asked how long Britain would wait before seeking more United Nations' or European Union sanctions against Iran over its nuclear program, Miliband said: "Now is not the time to be rushing for more sanctions."

"Now is the time to be backing the American outreach that is a once-in-a-generation opportunity, not just for us but for the Iranians," he said.

The powers suspect Iran wants to build nuclear weapons, an allegation denied by Tehran, which says it only seeks peaceful nuclear energy. The U.N. Security Council has imposed three rounds of sanctions on Tehran.

Miliband said it made sense for the United States to complete its review of Iran policy and to ensure its overtures to Tehran were "clarified for the Iranians."

"We can then ensure that, if the Iranians do not respond in a way that is positive, further steps can be taken," he said.

U.S. Secretary of State Hillary Clinton has said repeatedly that the United States is prepared to impose more punitive measures on Iran as long as it refuses to give up sensitive nuclear work.

On March 20, Obama released a video message to Iran offering a "new beginning." Iran has given a guarded response to Obama's overtures.

A senior U.S. diplomat met Iran's delegate at an international conference on Afghanistan in The Hague on Tuesday in a sign of tentatively improving ties.

Miliband said there was a "range of options on the table" for international cooperation with Iran on a civil nuclear power program, but he gave no details.

Miliband also said Britain had taken no decision to send more troops to Afghanistan and had not been asked to do so by the United States.

The head of the British army, General Richard Dannatt, told the Times newspaper last week that British troop numbers in Afghanistan could rise to somewhere between the current level of 8,300 and 12,000.

Prime Minister Gordon Brown will discuss strategy on Afghanistan and Pakistan with Obama in London on Wednesday, Miliband said.

(Reporting by Adrian Croft; Editing by Angus MacSwan)