Haiti marked the fifth anniversary Monday of the massive earthquake that ravaged an already desperately poor nation, even as it sought a way out of its latest debilitating political crisis.

Five years after the unprecedented category seven quake killed at least 300,000 people and left more that a million homeless, the nation paused for a "Day of Reflection and Commemoration."

President Michel Martelly led the official tributes, calling for unity to better prepare Haiti for its next challenge, but the government's three-year failure to organize elections has undermined his authority.

Laying flowers at a monument in Place St Christophe in the still damaged capital, he paid tribute to the sacrifice of Haitian and foreign rescuers who flocked to Port-au-Prince in 2010.

"Five years later, are we ready to face other catastrophes that could strike Haiti?" he asked.

Haiti's most immediate challenge is not another natural disaster, however, but institutional breakdown combined with persistent poverty.

As of Monday, parliament's mandate ended with no date set for a new election, raising the prospect that Martelly might be left ruling by decree like the country's former dictators.

A last-minute accord signed Sunday to resolve the institutional impasse was not ratified by parliament before its authority expired, creating a perilous political and institutional vacuum.

Martelly's supporters have blamed the opposition for failing to pass an electoral law that would allow voting, but his opponents accuse him of provoking a stalemate in order to rule alone.

Sunday's apparent deal was welcomed by foreign powers, but it was not immediately clear whether it would have any weight.

There have been mounting street protests against the government as the political crisis deepens, but on Monday the city was more quiet than usual as Haitians mourned their dead.

At Port-au-Prince's still ruined cathedral, members of the country's Catholic majority gathered to lay flowers and ponder the future.

In the immediate aftermath of the quake, more than 1.5 million were homeless. The number living under canvas and in refugee shanty towns has fallen to 70,000, but Haitians remain pessimistic.

"Nothing has changed," lamented 24-year-old international affairs student Mirlie St-Preux. "Reconstruction has focused on a few public buildings. We need more foreign aid."

- Weak governance -

Many of those paying their respects Monday agreed, and not just opposition activists. Some complained that what building there had been was unsupervised and vulnerable to future shocks.

The World Bank's envoy to Haiti, Mary Barton-Dock, insists there has been tangible economic progress and poverty reconstruction, though significant challenges lie ahead.

"Haiti remains the country with the greatest income inequality in the Latin America and Caribbean region," she said.

"Weak governance continues to impede the delivery of essential services, such as electricity."

The World Bank and other international donors fear that Haiti's limited recovery since the quake could be undermined if the political crisis and resulting unrest continues.

But an 11th-hour bid to put the constitutional process back on track -- a vaunted agreement between Martelly and a senior panel of stakeholders to hold elections this year -- failed at the first hurdle.

An insufficient number of lawmakers from the outgoing parliament gathered overnight to ratify the deal, and the constitutional situation was still confused as the ceremonies began Monday.

Washington has been pressing for a parliamentary election to be held, and the European Commission welcomed what appeared to have been a breakthrough on Sunday.

"Haiti needs steady and effective government and constructive opposition... to steer the nation towards sustainable development," EU foreign affairs chief Federica Mogherini said.

Would-be prime minister Evans Paul, named by Martelly on December 26, has been unable to take office as a result of the political friction between the president and lawmakers.

A group of senators has proposed a new premier be chosen.

Meanwhile, UN Secretary-General Ban Ki-moon has urged the international community to keep contributing aid to Haiti and congratulating its people on their perseverance.