The more cautious approach appeared to seek a middle ground: showing a bond with Ahmadinejad without the elaborate display and deep symbolism of kissing his hand.

Iranian President Mahmoud Ahmadinejad (R) kisses Supreme Leader Ayatollah Ali Khamenei after he received a certificate declaring him as president of the Islamic Republic of Iran from Khamenei in Tehran August 3, 2009. [Agencies]

Missing from Monday's ceremony was Khomenei's grandson, Hasan Khomeini, who has supported the reformists. Reformist Web sites say he deliberately left Iran to avoid attending this week's inauguration events.

Mousavi and many other leaders of the reform movement had roles in the Islamic revolution or the early years of the system that replaced the Western-backed monarchy.

Their current protests have borrowed some of the tactics of the revolution, including shouting Allahu Akbar from rooftops in a nightly protest and using funerals and 40-day memorials for decreased demonstrators as rallying points for protests.

In the early months of Ahmadinejad's second, four-year term, Iran faces some important tests.

President Barack Obama has given Iran a September deadline to show a willingness to open dialogue on its nuclear ambitions and other key issues.

But Ahmadinejad has given no hints of major policy concessions ahead.

In a July 16 speech, he again vowed to push ahead with Iran's nuclear program. He also said Iran wants "logic and negotiation" with the West but insisted the US apologize for its interference in the elections. Iran, he declared, would become a world power that "will bring down the global arrogance" - one of the phrases often used for the United States.

Iran's leadership is also desperate to show cohesion at home.

Ahmadinejad opened a brief - but potentially disruptive - confrontation with Khamenei's ruling theocracy in late July by refusing to drop his top deputy, Esfandiar Rahim Mashai, who angered conservatives last year when he made friendly comments toward Israelis. But Ahmadinejad relented and dropped Mashai.