In tent cities, outside demolished churches, and at the mass graves that have become a symbol of their appalling loss, the people of Haiti paused yesterday to mark the one month anniversary of the natural disaster that killed 230,000 people and left millions more struggling for survival.

Thousands of survivors gathered across Haiti's capital, Port-au-Prince, to commemorate the 12 January earthquake that killed 125,000 people. (REUTERS / IVAN ALVARADO) The national day of mourning brought the shell-shocked nation together to honour victims of the devastating earthquake, which measured 7.0 on the Richter scale, flattened much of the capital city, and made an estimated 1.2 million of its citizens homeless.

Priests from Haiti's two official religions, the Catholic and Voodoo faiths, joined Protestant clergymen at yesterday's main remembrance service, held under mimosa trees outside the presidential palace in Port-au-Prince.

They were watched by the 125,000 victims who are now living under makeshift tarpaulins in the nearby park. Like many mourners across the city, they wore black armbands, and sang hymns and gospel music.

The country's president, Réne Préval, whose administration is under increasing political pressure, wept throughout the service. He was comforted by his wife. "Haiti will not die; Haiti must not die," he said.

At 4.35pm local time, the moment the quake struck, Haitians at home and abroad kneeled to pray. They remained silent for 40 seconds, as long as the ground shook that fateful January day.

Yesterday's anniversary was also marked at hundreds of smaller religious events. Churches in the Petionville suburb were so packed that loudspeakers had to be set up. "All families were affected by this tragedy and we are celebrating the memory of the people we lost," one mourner, Desire Joseph Dorsaintvil, told Associated Press.

The day of mourning allowed the nation to catch its breath, after weeks of chaotic emergency operations. It also provided an opportunity to reflect on the challenges that face aid workers battling to treat the injured and feed, clothe, and provide water to survivors.

Although the immediate crisis has receded, and the largest humanitarian relief effort ever mounted is now underway, millions of refugees will soon have to contend with the hurricane season, which begins in earnest in April.

The government said this week that rains could become the biggest threat to recovery. Flooding will damage already-limited sanitation, and aid workers fear it could turn crowded camps into outdoor sewers.

"There's a massive concern about the possible outbreak of disease, and so we are working to combat that quickly," Aisha Bain of the International Rescue Committee told CNN. "We are working on a large-scale buildup of providing clean water, latrines, showers, hand-washing stations."

The coming rainy season could also affect the long-term success of reconstruction efforts. The European Union has proposed a military mission to step up the construction of shelters, while charities campaign to provide tents.

However Port-au-Prince is running out of space to pitch new tents, which take up more room than makeshift shelters: "Tents are great, but they basically impede the process of economic development and reconstruction," Lewis Lucke, the US special co-ordinator, told CBC news.

Tens thousands of Haitians have meanwhile fled overseas. However some foreign countries have begun turning away refugees, leading to fears from the UN refugee agency, UNHCR, that they will return to the country and add to local problems.

"We are concerned about the large numbers of highly vulnerable people, including the injured and separated or orphaned children," the UNHCR said yesterday, "Therefore until such time as people can return safely and sustainability, [we] call on all countries not to return Haitians and to continue granting interim protection on humanitarian grounds."