World powers trying to resolve the nuclear dispute with Iran have failed to agree on a unified strategy for the United Nations Security Council.

U.S. Secretary of State Condoleezza Rice and foreign ministers from other permanent Security Council members met for several hours in New York late Monday. Envoys from Germany and the European Union also took part.

Britain's new Foreign Secretary, Margaret Beckett, says the lengthy session was an "important but difficult meeting."

A senior U.S. official says the ministers agreed that Iran must not have nuclear weapons capabilities, but could not reach an accord on how to enforce this view. The American official, who asked not to be named, adds it is unlikely that a consensus can emerge in time for a Security Council vote this week. The countries involved are likely to hold more talks, Tuesday.

Earlier Monday, the White House received a letter from Iran's President Mahmoud Ahmadinejad, which Tehran had described as a possible "new solution" to the international crisis. Secretary of State Rice says the 18-page message discusses history, philosophy and religion, but does not represent a breakthrough in the dispute.

Other senior officials dismissed the surprise letter as a "diversionary tactic."

The United States' director of national intelligence, John Negroponte, told reporters the timing of the letter suggests Tehran is trying to undermine efforts for a binding Security Council resolution ordering Iran to suspend all uranium enrichment.

The United States suspects Iran is trying to build a nuclear weapon. Iran insists its nuclear program is for civilian energy use.

Mr. Ahmadinejad's letter was sent through the Swiss Embassy in Tehran. It is the first known high-level contact between the United States and Iran since April 1980, when diplomatic ties were cut during the Iranian hostage crisis.

China and Russia, whose foreign ministers took part in the meeting with Rice in New York, say they will veto sanctions or any move that threatens military force against Iran.