PORT-AU-PRINCE, Haiti — The world's bill for the Haitian earthquake is large and growing — now $2.2 billion — and so is the criticism about how the money is being spent.

A half-million homeless received tarps and tents; far more still are waiting under soggy bed sheets in camps that reek of human waste. More than 4.3 million people got emergency food rations; few will be able to feed themselves anytime soon. Medical aid went to thousands, but long-term care isn't even on the horizon.

International aid groups and officials readily acknowledge they are overwhelmed by the scale of the disaster. Haitian leaders — frustrated that billions are bypassing them in favor of U.N. agencies and American and other non-governmental organizations — are whipping up sentiment against foreign aid groups they say have gone out of control.

In the past few days, someone scrawled graffiti declaring "Down with NGO thieves" along the cracked walls that line the road between Port-au-Prince's international airport, the temporary government headquarters, and a U.N. base.

Ahead of a crucial March 31 post-quake donors conference in New York, many are taking a hard look at the money that's flowed in so far.

First the good news: Assistance has indeed been pouring into Haiti, sometimes from unexpected places.

An analysis of U.N. data shows that private donations make up the bulk of the total, accounting for more than $980 million of what already has been delivered or that donors have promised.

The United States leads all countries with its commitments of $713 million — with Canada, France, Spain, the United Kingdom, Japan and the European Union among other top donors. Saudi Arabia poured $50 million of its oil wealth into the U.N. Emergency Response Relief Fund.

Even countries with their own troubles rushed to Haiti's aid: Afghanistan provided $200,000.

A Nevada real estate developer agreed to send $5 million worth of circus tents formerly used by Cirque du Soleil. Leonardo DiCaprio and Coca-Cola are each sending $1 million. Dollar General is donating $100,000. Hanesbrands is shipping 2 million pairs of underwear.

But leaders including Prime Minister Jean-Max Bellerive are not happy with the way the aid money is being delivered.

"The NGOs don't tell us . . . where the money's coming from or how they're spending it," he told the Associated Press. "Too many people are raising money without any controls, and don't explain what they're doing with it."

Haiti wanted aid organizations to register with the government long before the quake, a goal identified as a priority by former U.S. President Bill Clinton when he was named U.N. special envoy in 2009. But it never was completed.

U.N. and U.S. officials said there is close monitoring of NGOs who receive funds. The U.S. Agency for International Development requires recipient groups to file reports every two weeks on how their activities are lining up with their planned programs, said Julie Leonard, leader of the agency's Disaster Assistance Response Team.