The staggering scope of Haiti's nightmare came into sharper focus Monday as authorities estimated that 200,000 are dead and 1.5 million homeless in the quake-ravaged heart of this tragic land, where injured survivors still died in the streets, doctors pleaded for help and looters slashed at one another in the rubble.

The world pledged more money, food, medicine and police. Some 2,000 U.S. Marines steamed into nearby waters. And ex-President Bill Clinton, a special U.N. envoy, flew in to offer support. Six days after the earthquake struck, search teams continued to pull buried survivors from the ruins.

But hour by hour, the unmet needs of hundreds of thousands of people grew.

Overwhelmed surgeons appealed for anesthetics, scalpels, saws for cutting off crushed limbs. Uncounted hundreds of survivors sought to cram onto buses headed out of town. In downtown streets, others begged for basics.

"Have we been abandoned? Where is the food?" shouted one man, Jean Michel Jeantet.

The U.N. World Food Program said it expected to boost operations from feeding 67,000 people on Sunday to 97,000 on Monday. But it needs 100 million prepared meals over the next 30 days, and it appealed for more government donations.

"I know that aid cannot come soon enough," U.N. Secretary-General Ban Ki-moon said in New York after returning from Haiti.

"Unplug the bottlenecks," he urged.

Priorities at airport

In one step to reassure frustrated aid groups, the U.S. military agreed to give aid deliveries priority over military flights at the now-U.S.-run airport here, the WFP announced in Rome. The Americans' handling of civilian flights had angered some humanitarian officials.

Looting and violence flared again Monday as hundreds clambered over the broken walls of shops to grab anything they could - including toothpaste, now valuable for lining nostrils against the stench of Port-au-Prince's dead. Police fired into the air as young men fought over rum and beer with broken bottles and machetes.

Hard-pressed medical teams sometimes had to take time away from quake victims to deal with gunshot wounds, said Loris de Filippi of Doctors Without Borders. In the Montrissant neighborhood, Red Cross doctors working in shipping containers and saying they "cannot cope" lost 50 patients over two days, said International Red Cross spokesman Simon Schorno.

Amid the debris and the smoke of bodies being burned, dozens of international rescue teams dug on in search of buried survivors. And on Monday afternoon, about 140 hours after the quake, they pulled two Haitian women alive from a collapsed university building. At a destroyed downtown bank, another team saved a trapped employee.

Many more dead

The latest casualty report, from the European Commission citing Haitian government figures, doubled previous estimates of the dead from the magnitude-7.0 quake, to approximately 200,000, with about 70,000 bodies recovered and trucked off to mass graves.

If accurate, that would make Haiti's catastrophe about as deadly as the 2004 Indian Ocean tsunami, which killed an estimated 230,000 people in a dozen countries.

European Commission analysts estimate 250,000 were injured and 1.5 million were made homeless. Masses are living under plastic sheets in makeshift camps and in dust-covered automobiles. Others have taken to the road seeking out relatives in the safer countryside.

On the capital's southern edge, thousands of people struggled to get onto brightly painted "tap-tap" buses heading out of town.

"We've got no more food and no more house, so leaving is the only thing to do," said Livena Livel, 22, fleeing with her 1-year-old daughter and six other relatives to her father's house in Les Cayes, near Haiti's western tip.

"At least over there we can farm for food," she said.

She said she was spending her last cash on the "insanely expensive" bus fare, jacked up to the equivalent of $7.70, three days' pay for most Haitians, because gasoline prices had doubled.

Water a concern

Getting clean water into people's hands was still a dire concern.

"People can survive a few days without food but we must try to avoid major outbreaks of waterborne disease," said Brian Feagans, a spokesman for the aid group CARE.

Clinton, accompanied by his daughter Chelsea, pitched in, helping unload cases of bottled water from their plane to a U.N. truck.

There also remained a "huge demand for lifesaving surgery for those who suffered terrible injuries," Doctors Without Borders reported.