World leaders on Tuesday welcomed the adoption of Iraq's new constitution, but some observers cautioned that the country still faces major obstacles on its path to stability. Britain's Foreign Secretary Jack Straw called the referendum an "important step" in the development of a democratic nation. Italy's foreign minister Gianfranco Fini said it marked "the beginning of a new era." But the United Nations said the vote also highlighted the sharp political divide between different groups in Iraq. "The results of the referendum have indicated the degree of political polarization in Iraq," the UN Assistance Mission to Iraq said in a statement. "This poses an ongoing challenge for all Iraqis and underscores the importance of an inclusive national dialogue." The constitution, considered another major step in Iraq's reconstruction, was supported by a majority of Kurds and majority Shiites, but opposed by many Sunni Arabs. The UN, which took part in the audit of the Oct. 15 referendum, said it was pleased with the high voter turnout among all of Iraq's ethnic groups and the professional manner in which the vote was conducted. Some 63 percent of eligible voters took part in the vote and the global body's representatives in Baghdad said they found no evidence of fraud. "The people of Iraq have demonstrated their commitment to a credible, inclusive and peaceful political process which augurs well for the December elections and the future of the country ... They deserve to be congratulated," the UN statement added. Amnesty International said the result _ while "important" _ ought not to distract attention from the security and basic needs of Iraqi civilians. "The constitution itself is an important step, but that should not distract attention from what is happening every day," said spokeswoman Nicole Choueiry. "Civilians continue to die in Iraq by the hundreds every month." America's allies lined up Tuesday to praise the result. "Today marks the beginning of a new era of dialogue and reconciliation among all Iraqi people, beyond ethnic and religious differences, and shows that politics has defeated the violence of terror," said Fini, who is also Italy's deputy prime minister. Italy sent about 3,000 troops to Iraq to help with reconstruction after the ouster of Saddam Hussein in 2003, though the government is gradually pulling some of its contingent out. Straw called the majority in favor of the constitution "striking" and paid tribute to the Iraqi voters, the country's electoral commission and the UN for its role in the peaceful referendum. "The Iraqi people have shown again their determination to defy the terrorists and take part in the democratic process," Straw said in Brussels. "Nearly ten million people voted." The European Union, which was divided on the US led-war in Iraq, said the vote was a "key step" toward building a country where "differences are settled through democratic dialogue." Turkish Prime Minister Recep Tayyip Erdogan, who rejected US requests to use its air space in the run-up to the Iraq war, said the adoption of the constitution "has opened the door wide to all sects to take part in the elections that will take place by the end of the year." Even if groups still disagree over some laws, "if they succeed in turning up in big numbers for the elections and from all sects, those elected can make the changes they see fit to the constitution," Erdogan told reporters in Kuwait. "This is the definition of democracy," he said through an interpreter into Arabic. Iraq's landmark constitution was adopted by a majority of voters during the country's Oct. 15 referendum, election officials said Tuesday. "Whatever the results of the referendum are ... it is a civilized step that aims to put Iraq on the path of true democracy," Farid Ayar, an official with the Independent Electoral Commission of Iraq, said before reading the final results at a news conference. The results indicated that Sunni Arabs, who had sharply opposed the draft document, had failed to produce the three-quarters "no" vote they would have needed in at least three of Iraq's 16 provinces to defeat it. The commission, which had been auditing the referendum results for 10 days, said at a news conference in Baghdad that Ninevah province had produced a "no" vote of only 55 percent. Only two other mostly Sunni Arab provinces, Salahuddin and Anbar, had voted no by two-thirds or more. Election commission officials and UN officials, who also took part in the audit, "found no cases of fraud that could affect the results of the vote," Ayar said. The constitution, which many Kurds and majority Shiites strongly support, is considered another major step in the country's democratic transformation, clearing the way for the election of a new Iraqi parliament on Dec. 15. Such steps are considered important in any decision about the future withdrawal of US-led forces from Iraq.