U.S. Army soldiers of the 82nd Airborne Division unload water bottles from a helicopter Wednesday at the international airport in Port-au-Prince. International aid flowing into Haiti after last week's earthquake has been struggling with logistical problems, and many people are still desperate for food and water.

PORT-AU-PRINCE, Haiti — Workers are carving out mass graves on a hillside north of Haiti's capital, using earth-movers to bury 10,000 earthquake victims in a single day while relief workers warn the death toll could increase.

Medical clinics have 12-day patient backlogs, untreated injuries are festering and makeshift camps housing thousands of survivors could foster disease, experts said.

"The next health risk could include outbreaks of diarrhea, respiratory tract infections and other diseases among hundreds of thousands of Haitians living in overcrowded camps with poor or nonexistent sanitation," said Dr. Greg Elder, deputy operations manager for Doctors Without Borders in Haiti.

The death toll is estimated at 200,000, according to Haitian government figures relayed by the European Commission, with 80,000 buried in mass graves. The commission now estimates 2 million homeless, up from 1.5 million, and says 250,000 are in need of urgent aid.

In the sparsely populated wasteland of Titanyen, north of Port-au-Prince, burial workers on Wednesday said the macabre task of handling the never-ending flow of bodies was traumatizing.

"I have seen so many children, so many children. I cannot sleep at night and, if I do, it is a constant nightmare," said Foultone Fequiert, 38, his face covered with a T-shirt against the overwhelming stench.

The dead stick out at all angles from the mass graves — tall mounds of chalky dirt, the limbs of men, women and children frozen together in death. "I received 10,000 bodies yesterday alone," said Fequiert.

Workers say they have no time to give the dead proper religious burials or follow pleas from the international community that bodies be buried in shallow graves from which loved ones might eventually retrieve them."We just dump them in, and fill it up," said Luckner Clerzier, 39, who was helping guide trucks to another grave site farther up the road.An Associated Press reporter counted 15 burial mounds at Clerzier's site, each covering a wide trench cut into the ground some 25 feet deep, and rising 15 feet into the air. At the larger mass grave, where Fequiert toiled, three earth-moving machines cut long trenches into the earth, readying them for more cadavers.Others struggle to stem the flow of the dead.More than eight days after the magnitude-7.0 earthquake, rescuers searched late into the night for survivors with dogs and sonar equipment. A Los Angeles County rescue team sent three dogs separately into the rubble on a street corner in Petionville, a suburb overlooking Port-au-Prince. Each dog picked up the scent of life at one spot.They tested the spot and screamed into the rubble.They heard no response, but vowed to continue."It's like trying to find a needle in a haystack, and each day the needles are disappearing," team member Steven Chin said.One rescue was reported. The International Medical Corps said it was caring for a child found in ruins Wednesday.

Eleanore Rose of the Canadian Red Cross holds a 6-month-old child at Hospital General in Haiti. The relief efforts in Haiti are a big test for the American Red Cross.