The United States may have missed its best opportunity in 2003 to hold a broad dialogue with Iran, with the result that Washington is now lagging behind the European Union in being able to have direct talk on Tehran's nuclear issues, the Washington Post reported on Sunday.

Iran had suggested putting everything on the table, including full cooperation on nuclear programs, acceptance of Israel and the termination of Iran's support for Palestinian militant groups, said the report, citing a 2003 proposal from Tehran for dialogue with Washington.

The proposal was faxed through the Swiss Embassy and received by the Near East Bureau of the State Department, just after the lightning takeover of Baghdad by U.S. forces three years ago, the report said.

But top Bush administration officials, convinced the Iranian government was on the verge of collapse, belittled the initiative. Instead, they formally complained to the Swiss ambassador who had sent the fax with a cover letter certifying it as a genuine proposal supported by key power centers in Iran.

Several former administration officials say the United States missed an opportunity in 2003 at a time when American strength seemed at its height, according to the report.

"At the time, the Iranians were not spinning centrifuges, they were not enriching uranium," Flynt Leverett, who was a senior director on the National Security Council staff then and saw the Iranian proposal, was quoted as saying.

He described it as "a serious effort, a respectable effort to lay out a comprehensive agenda for U.S.-Iranian rapprochement."

Trita Parsi, a Middle East expert at the Carnegie Endowment for International Peace, said he obtained the actual document from Iranian sources. The Washington Post said it had confirmed its authenticity with Iranian and former U.S. officials.

The document, the newspaper said, lists a series of Iranian aims for the talks, such as ending sanctions, full access to peaceful nuclear technology and a recognition of its "legitimate security interests."

Iran agreed at the time to put a series of U.S. aims on the agenda, including full cooperation on nuclear safeguards, "decisive action" against terrorists, coordination in Iraq, ending "material support" for Palestinian militias and accepting the Saudi initiative for a two-state solution in the Israeli-Palestinian conflict.

The document also laid out an agenda for negotiation, with possible steps to be achieved at a first meeting and the development of negotiating road maps on disarmament, terrorism and economic cooperation.

The newspaper quoted Parsi as saying that the U.S. victory in Iraq frightened the Iranians because U.S. forces had routed in three weeks an army that Iran had failed to defeat during a bloody eight-year war.