Baghdad, Iraq ? For an hour anyway, Iraqi leaders put aside their disagreements during the signing of a landmark interim constitution Monday, heaping praise on the U.S.-backed document amid patriotic songs and Quranic verses urging unity. But sectarian differences resurfaced as soon as the event ended.

The Shiites’ most influential cleric, Grand Ayatollah Ali al-Husseini al-Sistani, issued a religious edict saying he had reservations about the interim constitution and that it would gain legitimacy only when adopted by an elected assembly.

His supporters on Iraq’s Governing Council pledged to try to amend parts of the charter, saying they effectively give minority Kurds and Sunni Muslims a veto over a permanent constitution due to be drafted and put to a referendum next year.

“This law places obstacles in the path of reaching a permanent constitution for the country that maintains its unity, the rights of its sons of all sects and ethnic backgrounds,” al-Sistani said.

Al-Sistani’s edict and the Shiite Muslim council members’ comments somewhat devalued the historic significance of the signing of a charter that promises to compensate Iraqis for years of oppression under Saddam Hussein, safeguard the freedoms and human rights of their ethnic and religious groups and lay down the foundations for a genuine democracy.

Senior Shiite clerics like al-Sistani are exploiting the void left by Saddam’s departure to exercise enormous influence on the U.S.-backed political process in a political arena once dominated by Sunnis but now controlled by a Shiite majority and a large Kurdish community.

Monday’s ceremony, held in Baghdad’s marble-and-glass Convention Center, kicked off with a recital of carefully chosen Quranic verses that urged Muslims to set aside their differences.

Later, children dressed in Arab, Assyrian and Kurdish costumes performed patriotic songs.

“The Executioner is gone, festivities will begin, we will wear colorful clothes now that sadness is behind us,” went one song that alluded to Saddam’s rule. The performance drew warm applause from the roughly 200 guests, including L. Paul Bremer, chief U.S. administrator in Iraq.

Members of the Iraqi Governing Council celebrate shortly after affixing their signatures on the new interim constitution. The historic signing ceremony, which took place Monday in Baghdad, was a key step in U.S. plans to hand over power to the Iraqis. Behind the delegates who signed the constitution was a map of Iraq with the words We