TEHRAN - Mahmoud Ahmadinejad will be sworn in as Iran's president on Wednesday after a disputed re-election that has exposed a deep schism in the clerical establishment.

Despite intense political feuding, Ahmadinejad will take his oath of office before parliament and then has two weeks to present a cabinet of ministers to the conservative-dominated assembly for approval.

Opposition websites said supporters of Ahmadinejad's main rival, Mirhossein Mousavi, were planning to gather in front of parliament to protest against the ceremony.

The vote, which leading moderates say was rigged to secure Ahmadinejad's re-election, sparked Iran's worst unrest since the 1979 Islamic Revolution. The authorities say the vote was the healthiest election since the revolution.

U.S. President Barack Obama and the leaders of France, Britain, Italy and Germany have all decided not to congratulate Ahmadinejad on his re-election.

But when asked whether Obama recognized Ahmadinejad as Iran's president, spokesman Robert Gibbs said: He's the elected leader.

Mousavi and fellow defeated moderate candidate Mehdi Karoubi reject the new government as illegitimate, defying Iran's most powerful figure, Supreme Leader Ayatollah Ali Khamenei, who backed the election result and endorsed Ahmadinejad.

At a ceremony on Monday, Khamenei described Ahmadinejad as courageous, hardworking and wise.

Leading moderates, including former president Mohammad Khatami and Akbar Hashemi Rafsanjani, were absent from the ceremony and hundreds of Mousavi supporters gathered at several Tehran squares but were dispersed by riot police.

DISARRAY

At least 20 people have been killed since the June 12 election and hundreds have been arrested.

In a mass trial on Saturday over 100 reformists, including several prominent figures, faced charges that include acting against national security by fomenting post-election unrest.

The next session of trial, denounced as a show trial by Khatami and Mousavi, will be held on Thursday.

Ahmadinejad is also under pressure from his hardline allies over his initial choice of first vice-president. He delayed for a week before obeying the leader's order to dismiss Esfandiar Rahim-Mashaie.

The disarray over Mashaie will likely complicate the president's choice of a new cabinet to present to parliament which may object if he names only members of his inner circle.

Tehran's diplomatic relations with the rest of the world are determined by the country's most powerful figure, supreme leader and paramount authority Khamenei.
Iran accuses the West, particularly the United States and Britain of fomenting vote unrests in the country to topple the clerical establishment. They deny the charge.

No change in foreign policy means no change in the standoff between Iran and the West over the country's nuclear program, which the United States and its European allies suspect is a front to build weapons, something Iran denies.

(Editing by Robin Pomeroy)