Washington  - Departing from long-standing policy, the Bush administration will send a senior diplomat to talks with Iran hoping to break a stalemate in the effort to curb Tehran's nuclear ambitions, the State Department said Wednesday.

Under Secretary of State William Burns, the third-highest US diplomat, will travel to Geneva this weekend to participate in a meeting with Iran's nuclear negotiator, Saeed Jalili, spokesman Sean McCormack said.

Iran is expected to respond to a package of diplomatic and economic incentives offered by five permanent members of the Security Council plus Germany last month in exchange for an Iranian pledge to halt uranium enrichment.

"Under Secretary Burns will attend the meeting as a participant," McCormack said. "He'll be there to listen. He'll be there to hear the Iranian response."

The decision to send Burns sends a strong signal from President George W Bush that he is committed to a diplomatic resolution to the dispute over Iran's nuclear activities, McCormack said, but added that "full-blown negotiations" with the United States will not take place until Iran complies with UN Security Council resolutions and suspends uranium enrichment.

"There's no change in the substance, but it sends a strong signal," McCormack said.

Burns will be part of the delegation on Saturday led by EU foreign policy chief Javier Solana, who has served as the lead negotiator with Iran and presented the package of incentives to Iran last month approved by Security Council powers Britain, China, France, Russia and the US.

The US severed diplomatic relations in 1980, following the 1979 storming of the US embassy in Tehran and subsequent hostage crisis. Burns' presence at the Geneva meeting would be the highest- level diplomatic meeting between the US and Iran since the Iranian Revolution.

If Iran suspends uranium enrichment the US and its Security Council partners plus Germany will meet with the Iranian delegation "anytime, anyplace, anywhere to talk about any variety of subjects," McCormack said. (dpa)