UN Secretary General Kofi Annan has said international support pledged towards rebuilding Iraq marks a "turning point" for the country.
The US and the EU say they stand shoulder to shoulder with Iraq
But he said the process would not be easy and Iraqis should take control of their own future.
Mr Annan was speaking at the end of a conference in Brussels that issued a declaration of support for Iraq.
The meeting was co-hosted by the EU and the US and attended by more than 80 countries and organisations.
"This conference marked a watershed for Iraq," Mr Annan said afterwards.
He said he hoped the long-suffering people of Iraq would "take heart from this strong message of support" and that the declaration would make future challenges "appear a little less daunting".
During the conference, Mr Annan told delegates the international community was determined to ensure that Iraqi reconstruction was a success.
He called for a "partnership that yields tangible benefits in the everyday lives of ordinary Iraqis".
Luxembourg Foreign Minister Jean Asselborn said the EU would work "shoulder to shoulder" with Iraq.
"The international community is committed to building a new Iraq, with stability, with democracy and with human rights and with constructive relations with its neighbours," Mr Asselborn said.
Iraqi officials outlined their reform plans and urged other countries to support their efforts.
"We have presented our visions and our priorities to you," said Iraqi Foreign Minister Hoshyar Zebari.
"Now it's your turn to look at those elements and those priorities to see where you can help."
US pressure on Syria
The role of Iraq's neighbouring countries was also mentioned in the final statement.
The conference called for more co-operation between Iraq and its neighbours in controlling the borders, and urged all countries to restore diplomatic ties with Baghdad.
But US Secretary of State Condoleezza Rice took a swipe at Syria, urging it to "live up to its responsibilities" in preventing militants from crossing into Iraq.
The EU and US said the aim of the conference was to give Iraq an opportunity to explain to the world what assistance it needed.
The meeting was also seen as a way for the US and Europe to put past differences over Iraq behind them.
"A democratic process is taking place that is vital for us, whether you were against the war or not," German Foreign Minister Joschka Fischer told reporters.
Ms Rice earlier said the international community would "support the Iraqi government along three important fronts - political reform, economic reconstruction and strengthening security with the rule of law".
The Brussels gathering was not a donors' conference - that will be held in Jordan next month.