Former U.S. President Bill Clinton - the U.N. Special Envoy for Haiti - returns to the earthquake-shattered country Friday to deliver supplies and meet with Haitian leaders.

The former president says he wants to ensure assistance continues to be "effective, coordinated and sustained, in the weeks and months to come."

The U.N. has asked Mr. Clinton to coordinate the international relief efforts for Haiti.

More than three weeks after the 7.0 magnitude quake left the capital, Port-au-Prince, in ruins, many survivors are living in tents made of bed sheets and still face a daily battle for adequate food, water and medical care.

The International Organization for Migration says aid agencies are racing to provide tens of thousands of tents and other supplies before the onset of the rainy season, which it says could begin at end of this month.  It says rains have already begun to fall in the southern town of Jacmel.

The IOM also notes that aid agencies are providing materials for the construction of sturdier transitional shelters, ahead of the start of hurricane season in June.

Officials say one million Haitians are homeless following the January 12 quake.  Prime Minister Jean-Max Bellerive said Wednesday that more than 200,000 people were killed and 300,000 injured.