— The Associated Press

PORT-AU-PRINCE, Haiti — A heavy downpour sent the throngs living beside Haiti’s shattered national palace cowering under tarps Thursday as the rush of water made much of the camp of earthquake victims impassable — an ominous foretaste of the rainy season to some.

Amputees struggled to maneuver through mud on crutches and wheelchairs.

Many in the makeshift tent cities housing nearly 600,000 people in Haiti’s capital still live without even plastic tarps, which the international community is trying to get to everyone by May 1.

So when the rain comes, bed sheets supported on sticks as protection from the sun quickly get soaked and people move in temporarily with neighbors who have waterproof tents. The lucky actually have beds off the ground.

”It’s hard to keep my kids clean. There’s too much rain, too much dirt,” said Joseph Dukens, 25, at the camp beside the national palace.

He pointed to his baby daughter, who had her leg amputated below her hip. ”It’s only going to get worse.”

The government, aid groups and foreign governments have been wrangling for five weeks over how to house earthquake survivors, but neither the weather nor the people are waiting.

Makeshift camps have hardened into shantytowns, adding a new dimension to the capital’s teeming slum life with an extra helping of disease, hunger and misery brought on by the Jan. 12 disaster, which killed more than 200,000 people.

People are in some very dangerous places: at the bottom of hillsides they know will collapse in a heavy rain or near riverbeds that are bound to flood. They are crowded into polluted areas where sanitation is limited and disease is starting to spread.

”The government has said for weeks that they have identified sites, but time is getting short and there has been little progress,” said Ian Bray, an Oxfam spokesman.

On Thursday, a group of U.S. senators sent a letter to President Obama urging the immediate relocation of displaced Haitians to higher ground before rain begins in earnest.

”Tragedy will strike again when the rain comes. We urge your administration to stress this point with President (Rene) Preval and Prime Minister (Jean-Max) Bellerive,” they wrote.

Sens. George LeMieux and Bill Nelson of Florida, Frank Lautenberg of New Jersey and Amy Klobuchar of Minnesota also encouraged long-term investment, micro-loans for small businesses and movement of commerce outside Port-au-Prince.

Maj. Gen. Floriano Peixoto Vieira Neto, the Brazilian commander of the U.N. peacekeeping force in Haiti, said he expects 2,000 more foreign troops to be in place by mid-March, joining 8,500 already there.

He said the peacekeeping mission is providing security across Haiti, including guarding the corridor used by humanitarian groups to truck in aid from the Dominican Republic.