WASHINGTON — US President Barack Obama urged the world on Tuesday to honor its pledges to help Haiti emerge from the nightmare of a devastating earthquake one year ago that killed a quarter of a million people.

The US leader, who presided over a major US humanitarian mission for the ill-starred state a year ago, also said Haitians must be in the lead as they fight back, and said a relief effort would take years, if not decades.

"On this day when our thoughts and prayers are with the Haitian people, my message is the same as it was last year. Haiti can and must lead the way, with a strong vision for its future," Obama said.

"The international community must now fulfill the pledges it has made to ensure a strong and sustained long-term effort," the president said in a written statement.

Obama warned that despite the saving of countless lives this year, and the fact that many Haitians had better access to food and health care than before the earthquake, serious deprivation remained.

"Too much rubble continues to clog the streets, too many people are still living in tents, and for so many Haitians progress has not come fast enough," he said.

"As we have said all along, helping the poorest nation in the Western Hemisphere recover from one of the worst natural disasters ever to strike our hemisphere will take years, if not decades."

Obama said that Americans had been inspired by the Haitian response to the disaster, and been generous in sending aid in difficult economic times, adding that Washington would remain an "enduring partner" for Haiti.

The aid picture for Haiti remains uncertain a year before the quake anniversary on Wednesday.

Most of the 5.3 billion dollars pledged for the first 18 months after the quake has been legally committed, according to the Interim Haiti Recovery Commission.

But only 1.2 billion dollars has been allocated to specific reconstruction projects and donors are reluctant to disburse funds because of fears over corruption and instability.

Future cash commitments are drying up as confidence evaporates in an reconstruction effort.

US Secretary of State Hillary Clinton noted that over the past year, "more than 140 nations came together to support Haiti in its time of need."

"That spirit of cooperation must continue if we are to help Haiti overcome this tragedy. The resilience of the people of Haiti continues to inspire us," she said in a statement.

"Their determination has set an example for all of us to follow and serves as a beacon of hope for the country's future. The United States continues to work with the Haitian people along with our international partners and non-governmental organizations to help catalyze Haiti's renewal."

The US Treasury meanwhile reaffirmed its pledge to provide aid to Haiti, which included a $120-million contribution to the Haiti Reconstruction Fund (HRF), a multi-donor fund administered by the World Bank, to help provide credit to small businesses.

Treasury Under Secretary Lael Brainard said, "Credit is an absolutely essential part of a sustainable economic recovery so we have worked closely with the IDB (Inter-American Development Bank), the World Bank, and the government of Haiti on a fund that enables small business owners to gain some breathing room and get back on their feet."

The US Treasury is also providing technical assistance to Haiti's finance sector.