The meetings focused on a wide range of issues, including postwar Iraq, in which the Bush administration is attempting to deter Iran from trying to influence the formation of a new government in Baghdad.
Secretary of State Colin Powell, during a news conference here after a meeting with Egyptian officials, said the administration opposes a fundamentalist regime as not being in the interest of the Iraqi people.
Powell echoed a similar statement weeks ago by Defense Secretary Donald H. Rumsfeld, who said establishment of an Iraqi-style fundamentalist government would be unacceptable to the United States.
The official, who spoke on condition of anonymity, said the meetings in Geneva were technically under the auspices of the United Nations.
USA Today, reporting on the talks in Monday's editions, said the government of Iran was weighing the possibility of reopening diplomatic relations with the United States for the first time in nearly a quarter century.
Powell, on a flight Saturday to the Middle East, said the United States has long been in communication with Iran through various channels. However, he said at the time that the administration was not trying to restore diplomatic relations with Tehran, which were broken off in 1979, when militants overran the U.S. embassy and took dozens of Americans as hostages.
In the days after U.S. troops drove Iraqi forces from Baghdad, Iraqi Shiites staged a number of demonstrations against American occupation, and several Shiite political factions boycotted the first postwar meeting organized by Central Command.
The U.S. accused Iran, which is Shiite dominated, of trying to influence Iraq through the 60 percent Shiite majority there, which was oppressed during the Saddam Hussein regime.
U.S. forces deployed along the Iran-Iraq border to prevent infiltration by Iranian agents and entered into a ceasefire with an anti-Iran terrorist group, the Mujahedeen al Khalq or People's Mujaheheen. That ceasefire was terminated last week and the group surrendered its weapons.
Iran was listed by President Bush as a member of the "axis of evil," apparently for its support for the terrorist group Hezbollah. Some advisers to the president have suggested military action against Iran, as well as Syria, as a continuation of the "war on terrorism."
However, Iran tacitly supported the U.S. war in Afghanistan and did not complain loudly when at least three U.S. cruise missiles were reported to hit Iran during the U.S.-led war on Iraq.
The U.S. and Iran are also locked in a dispute over what Washington alleges is a secret nuclear weapons program by the Iranians. Tehran insists its nuclear activities are civilian in nature.
Mr. Bush said one benefit of the war in Iraq would be the transformation of the Middle East, especially its autocratic regimes.
It is unclear if the talks with Iran will validate the president's strategy.
Threatening rhetoric towards Syria after the war gave way to talks, and now Damascus might resume negotiations with Israel and is considering domestic reforms.