U.N. Secretary-General Kofi Annan on Friday urged the United States to join with Europe to resume talks with Iran and to "lower the rhetoric" in the international standoff over Tehran's nuclear program.

"I have asked all sides to lower the rhetoric and intensify diplomatic efforts to find a solution," Annan told reporters in the margins of an EU-Latin America summit.

"Everyone, every important stakeholder should be at a table," Annan said. "I urge all parties to be open, Iran included, and come back to the table and find a solution."

Annan said proposed talks between the European Union countries of Britain, Germany France with Iran, would be more productive if they included the United States.

Washington however, has so far refused to take part and directly negotiate with Tehran.

"I have insisted very clearly both in private in my contacts with the American administration and publicly that I think it's important that the United States come to the table, and that they should join the European countries and Iran to find a solution," Annan said.

The EU and the United States fear Iran's nuclear program is being used to develop nuclear weapons. Tehran said it wants to make nuclear power.

At a meeting Tuesday, representatives of the U.S., Russia, China, Britain, France and Germany agreed to tell Iran the possible consequences of its refusal to halt its uranium enrichment program and the benefits if it abandons it.

U.S. Secretary of State Condoleezza Rice said Wednesday she and her counterparts on the U.N. Security Council agreed to give Iran another two weeks to reconsider its position.

Both China and Russia have so far refused to sign on to a U.N. resolution, which would declare Iran a threat to international peace and security and set the stage for further measures, which could range from breaking diplomatic relations to economic sanctions and military action, if Tehran refuses to comply.