Talks between Rice and Iranian Foreign Minister Manouchehr Mottaki would be one of the highest-level encounters between Washington and Tehran since the 1979 revolution turned Iran from a close U.S. ally into the arch-foe Islamic Republic.

Washington has accused Iran of fomenting violence in Iraq and U.S. officials have said if Rice met Mottaki she would call for an end to the flow of arms and foreign fighters into Iraq as well as training of insurgents. Tehran rejects the charges.

U.S. President George W. Bush's administration has dropped once resolute opposition to high-level contacts with countries like Iran and Syria as it seeks ways to end the Iraqi conflict.

A formal meeting has not been set up between Rice and Mottaki while they are in the Egyptian Red Sea resort of Sharm el-Sheikh, but she has made clear she would not avoid it.

"If we encounter each other and wander to other subjects I am prepared to address them at least in terms of American policy," Rice told reporters on Wednesday.

Rice has said she would not cut off a conversation if it turned to Tehran's nuclear program. The United States accuses Iran of having a secret program to build nuclear weapons, a charge Tehran denies.

U.S. and Iranian envoys spoke to each other directly about Iraq at regional talks in Baghdad in March. The U.S. envoy called the exchange "frank and sometimes even jovial".

The United States broke off diplomatic relations with Iran in 1980 over the 1979-81 hostage crisis when Iranian students held 52 U.S. citizens for 444 days.

INFLUENTIAL

Western diplomats acknowledge Shi'ite Muslim Iran is an influential force on Iraq, both as a neighbor and because of its links with elements in the Shi'ite-led Iraqi government.

The meeting in Sharm el-Sheikh on Thursday will discuss a five-year plan offering Iraq financial and political support in return for reforms.

On Friday, Iraq's neighbors as well as ministers from the Group of Eight leading industrialized nations and the European Union will discuss how to stabilize Iraq, where sectarian violence threatens to plunge the country into civil war.

Syria will also be in Sharm el-Sheikh and U.S. State Department spokesman Sean McCormack has said it was an "open possibility" Rice would meet Syrian officials to discuss substantive issues concerning Iraq.

Iraqi Foreign Minister Hoshiyar Zebari said he believed Rice would meet Syrian Foreign Minister Walid al-Moualem. It would be the first time she has met a Syrian foreign minister since taking office in 2005.

For more than two years, the United States had said talks with Syria were futile because Damascus had not met U.S. demands on Middle East issues.

A Syrian diplomat, who asked not to be named, said Damascus had been unable to persuade the Iraqi government to set a timetable for a U.S. troop withdrawal.

U.S.-led forces invaded Iraq in March 2003 to topple Saddam Hussein, but more than 150,000 U.S. troops have since failed to stamp out sectarian violence and defeat insurgents who draw support from the Sunni Arab minority once-dominant under Saddam.

Rice tried to dampen expectations about how successful the two days of meetings in Sharm el-Sheikh would be.

"Let's not have over-reaching expectations. It will take some time to overcome suspicions in the region," she said.

Hassan Nafaa, a political scientist at Cairo University, said: "As long as there is no direct dialogue between the Americans and the forces of resistance in Iraq there will be no solution at all."