More than 500,000 people were feared dead in Haiti after the quake razed homes, hotels and hospitals, leaving the capital in ruins and bodies strewn in the streets. With thousands of people missing, dazed survivors wandered through the rubble as more than 30 aftershocks rocked the ramshackle capital, where more than 2 million people live, most in severe poverty.

Death was everywhere in this devastated city of 2 million. Bodies of tiny children were piled next to schools. Corpses of women lay on the street with stunned expressions frozen on their faces as flies began to gather. Bodies of men were covered with plastic tarps or cotton sheets.

"Please take me out, I am dying. I have two children with me," a woman told a journalist from under a collapsed kindergarten.

At a triage center improvised in a hotel parking lot, people with cuts, broken bones and crushed ribs moaned under tent-like covers fashioned from bloody sheets.

"There's no water," said doctors' assistant Jimitre Coquillon. "There's nothing. Thirsty people are going to die."

"It's the most horrific thing I've ever seen," Bob Poff, a Salvation Army worker in Port-au-Prince, told MSNBC. "We have to get food and water" quickly, he said, in describing conditions that range from stifling heat to numerous aftershocks. "We're trying to stay alive."

As nations around the world mobilized to send help, Preval said at least thousands of people were probably killed. Haitian Sen. Youri Latortue said 500,000 could be dead, but conceded that nobody really knows.

Doctors Without Borders said its three hospitals in Haiti were unusable and it was treating the injured at temporary shelters.

The international Red Cross said a third of the country's 9 million people may need emergency aid, a burden that would test any nation and a crushing catastrophe for impoverished Haiti.

Residents wander amid the ruins of their town, a day after the earthquake that hit Port-au-Prince on Wednesday, Jan. 13.

An injured man is transported on a pushcart in Port-au-Prince.

An injured woman is helped after being rescued. An official with the International Red Cross said an estimated 3 million people may have been affected by the disaster.

A body lies among the rubble of a damaged building in Port-au-Prince.

Injured people are carried away in a truck.

Bodies are covered in blankets and moved to the side of the road.

An injured victim rests after surviving the 7.0-magnitude quake.

A man looks at a corpse in Port-au-Prince. Many survivors checked the dead to see if they were family or friends.

Many survivors in Port-au-Prince had nowhere to go the day after the quake.

Bodies lie in the rubble of one of the thousands of Port-au-Prince buildings that collapsed.

An injured resident waits for medical attention Wednesday in Port-au-Prince.

Injured people are evacuated on Jan. 13.

An injured man carries his dead daughter on Jan. 13. People pulled bodies from collapsed homes, covering them with sheets and placing them by the side of roads.

Residents sleep in the streets of Port-au-Prince hours after the earthquake.