WASHINGTON (AFP) — Six world powers have completed the details of a "refreshed" offer they will present to Iran in an effort to persuade it to halt its controversial nuclear activities, a US official said Friday.

The United States, Britain, France, Germany, Russia and China agreed earlier this month to make a new offer to Iran, but a date has yet to be set for it to be delivered to the Islamic republic.

"We have completed work on the details of the package and the accompanying letter," US State Department spokesman Sean McCormack told reporters.

The European Union's foreign policy chief, Javier Solana, will contact the Iranian government to "work on a date and venue for a meeting where representatives of the (six nations) can hand over and discuss this refreshed package," he said.

McCormack reiterated, however, that the United States would not be sending a representative. "We are not going to have a physical presence here," he said.

According to diplomatic sources, negotiations are under way with Iranian officials to send to Tehran a delegation of political directors from foreign ministries.

The West fears Iran could use uranium enrichment to make atomic weapons but Iran denies this is its aim, insisting it has a right to enrichment to make nuclear fuel as a signatory to the nuclear Non-Proliferation Treaty.

The UN Security Council has imposed three sets of sanctions on Iran to force it to stop enrichment, but the measures have failed to dissuade the government.

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