Tens of thousands of Shiite Muslims whistled, cheered and waved flags as Iranian President Mohammad Khatami (search) drove through the streets of Beirut on Monday, making the first visit by an Iranian president to Lebanon.

Khatami was met at Beirut airport by Lebanese President Emile Lahoud, Prime Minister Rafik Hariri and Cabinet ministers, and Sheik Naim Kassem, the deputy leader of Hezbollah (search) — the leading Shiite militant group in Lebanon.

Iran, a Shiite-majority country, is the main financial backer of Hezbollah, which periodically attacks Israel across the south Lebanese border and is listed as a terrorist group by the United States.

Hezbollah's inclusion in the red-carpet reception for Khatami was a departure from protocol that signalled the group's acceptance in mainstream politics.

As Khatami was driven to the city center, tens of thousands of Shiites lined the highway, applauding and waving the yellow flags of Hezbollah, the green flags of the rival Shiite group Amal (search), as well as Iranian and Lebanese flags.

Women threw rose petals as the president's convoy passed through the Shiite-dominated suburbs of south Beirut. Other well-wishers held up pictures of Khatami.

Shiites are the largest sect in Lebanon, an estimated 1.2 million people out of a population of 3.5 million. Both Hezbollah and Amal had urged supporters to welcome Khatami.

In a commentary published in the Lebanese newspaper As-Safir on Monday, Khatami said the American and British troops should immediately withdraw from Iraq and allow the "formation of a popular government."

Khatami said the coalition forces had suffered a moral defeat in Iraq.

"And the greatest mistake will be if the invasion forces attempt to impose on the (Iraqi) people a system that is immoral and alien," he said.

He said the American people "must not allow a special group with false ideas and dangerous ways of operating to use their national capabilities to preserve its own private interests."

In an interview with the official Iranian news agency on Sunday, President Lahoud said Khatami's visit would shore up support for Lebanon as a center for resistance against Israel.

Hezbollah was the most active of the militant groups that fought against Israel's nearly 20-year occupation of southern Lebanon, which ended in 2000.

Lahoud said Lebanon will never forget Iran's support for the Lebanese resistance against the Israelis, the Islamic Republic News Agency (search) reported.

U.S. Secretary of State Colin Powell discussed Hezbollah when he held talks with Syrian President Bashar Assad on May 3 in Damascus. Syria acknowledges giving political support to Hezbollah but denies channeling arms to the group.

Syria, which Khatami is scheduled to visit on Wednesday, dominates Lebanon and stations thousands of troops in its western neighbor.

During his three-day visit, Khatami is expected to sign an agreement granting Lebanon a soft loan of $50 million to finance various projects.

Although Monday's visit is the first by an Iranian president since the Islamic revolution overthrew the monarchy in 1979, it is not Khatami's first visit to Lebanon. He came to the country a few months before his first election as president in 1997.