As potential donors gather at the United Nations to assemble a fund to help rebuild earthquake-battered Haiti, the White House is asking Congress for additional spending to contribute to the reconstruction effort.

Haiti is hoping to raise $3.9 billion at the March 31 donors’ meeting to cover the initial 18-month phase of what is certain to be a lengthy reconstruction. The estimated total rebuilding cost is $11.5 billion, the U.N. says.

More than 220,000 were killed in the Jan. 12, magnitude-7 quake, and an estimated 2 million people are living in temporary shelter in Port-au-Prince or have moved away from the devastated capital to live elsewhere in Haiti. The earthquake caused an estimated $7 billion in damage.

President Obama is seeking more than $2.8 billion for relief and rebuilding in Haiti. His request, sent to Congress on March 24, includes about $800 million for reconstruction-related work.

Funds targeted for rebuilding include $749.3 million for “reconstruction needs to provide essential services,” such as housing, water, sanitation and electricity infrastructure, as well as roads, bridges and ports, the White House says.

Up to $120 million of that $749.3 million would be a U.S. contribution to the envisioned multidonor Haiti recovery trust fund. The White House request also includes $84.5 million to replace U.S. Embassy housing in Haiti damaged by the quake.

Other portions of the $2.8-billion supplementary appropriations request include reimbursements to federal agencies for costs they incurred in relief work shortly after the quake struck.

Also included in the White House proposal is $212 million toward a multilateral plan to cancel Haiti's debt.