The Brussels meeting of more than 80 countries and organisations was the first of its kind since the historic January elections installed an interim Iraqi government.
The co-sponsorship of the conference by the US and Europe marked a significant improvement in trans-Atlantic relations that had soured after Washington led the invasion of Iraq without UN backing.
It also offered an opportunity for world leaders to reiterate their support for providing aid and expertise to help Iraqis establish democratic political institutions, security forces, and to revive the country’s economy.
But there were also calls for Iraq to do more to help speed up the delivery of donations pledged in previous conferences.
Iraqi officials said aid had been slow in coming partly because of fears over security and corruption.
UN chief Kofi Annan and US Secretary of State Condoleezza Rice said Iraq must take steps to merit the support on offer.
Mr Annan said Iraq’s future “lies in the hands of the Iraqis themselves,” who must assume responsibility for regaining security, generating employment, providing basic services and protecting human rights.
He said the drafting of a new constitution, which must be completed by August ahead of December elections, was a “seminal opportunity” to create a country ruled by law and represented by all ethnic and religious groups.
Iraq’s neighbours were called on to work harder at staunching the flow of extremist militants into Iraq who have been fuelling the insurgency.
Ms Rice explicitly criticised Damascus saying that “Syria, in particular, must secure (its) borders from those who seek to destroy Iraq’s progress.”
A fresh series of car bombings in Baghdad, which left at least 18 people dead and injured dozens more, underscored the point.
Such daily attacks have stalled plans to modernise Iraq’s economy and nail down a timeframe for the pull-out of the 160,000 foreign troops stationed in the country.