UN Secretary-General Ban Ki-moon Wednesday asked former U.S. President Bill Clinton, already deeply involved in Haiti before last month's devastating earthquake as the UN special envoy to the small island country, to assume a leadership role in coordinating international aid efforts, from emergency response to reconstruction, following the disaster.

Ban and Clinton met at the UN Headquarters in New York on Wednesday morning, and "the secretary-general said he could not think of a better suited leader than President Clinton to do this," UN spokesman Martin Nesirky told a news briefing. "The aim is to provide strategic guidance to the UN involvement at the international level."

International efforts to help the poorest country in the Western Hemisphere after the Jan. 12 quake, which killed up to 200, 000 people, injured many others and left 2 million in need of aid, have faced a series of daunting challenges compounded by the enormity of the catastrophe and the lack of infrastructure in providing sufficient food, shelter and other requirements.

Clinton will work together with UN Development Program (UNDP) Administrator Helen Clark and Ban's Special Representative Edmond Mulet. Ban appointed Clinton the UN special envoy for Haiti last May, following a visit they made together two months earlier to raise awareness of efforts to help its people and government bolster economic security.

The provision of shelter remains an urgent need and the inter-governmental International Organization for Migration (IOM), which is coordinating this sector, estimates that 1.1 million people are displaced. UN officials have warned that there is an overwhelming need to provide shelter quickly ahead of Haiti's rainy season, which could start as soon as the end of this month.

Aid agencies have already distributed 10,000 family tents and more than 11,000 tarpaulins, while a further 15,000 tents are in stock and more than 40,000 should arrive in the coming days and weeks, IOM said.

On food distribution, the UN World Food Program (WFP) has scaled up its operation with the first systematic food distribution program using coupons, which started this weekend. The agency has now reached almost 1 million people since the quake struck, with more than 300,000 gaining access through the new distribution system in the last 72 hours.

WFP's emergency operation has now been extended until the end of 2010 and is likely to cost over 800 million U.S. dollars, more than double the initial budget. "The world has saved many lives in Haiti through an enormously generous and fast response to WFP's food and logistics appeal," Executive Director Josette Sheeran said Wednesday. "The humanitarian lifeline is now reaching millions of destitute women and children in Haiti. We are very grateful."

UN Children's Fund (UNICEF) Executive Director Ann M. Veneman was leaving Wednesday for the Dominican Republic on the first stop of a visit to Haiti, as the agency launches a massive immunization campaign aimed at reaching 500,000 children under the age of seven.

She will arrive in Port-au-Prince, the capital of Haiti and a city devastated by the quake, on Thursday and spend the day with children in the city and visit an immunization center for measles, diphtheria and tetanus, all of which can be deadly in times of crises. She will then return to the Dominican Republic where UNICEF is working to supply Haitian relief efforts.

The UN Stabilization Mission in Haiti (MINUSTAH) reported Wednesday that the security situation remains calm, despite isolated incidents in the past few days. Following an attack on a food convoy in Jeremie at the weekend, 14 suspects were arrested by Haitian National Police, assisted by MINUSTAH police and peacekeepers stationed in the area.