Traumatized Haitians slept out in parks and streets on Thursday, fearing aftershocks to the catastrophic earthquake that flattened homes and government buildings and buried countless people.

Tens of thousands of people were feared dead and many were believed to be still trapped alive in the rubble of the major 7.0 magnitude quake that hit Haiti's capital on Tuesday.

There were no signs of organized operations to rescue those trapped in debris or remove bodies and doctors in Haiti, the poorest country in the Western Hemisphere, were ill-equipped to treat the injured.

Survivors feared returning to their precarious homes and slept in open areas where groups of women sang traditional religious songs in the dark and prayed for the dead.

"They sing because they want God to do something. They want God to help them. We all do," said Hotel Villa Creole employee Dermene Duma, who lost four relatives.

Foreigners slept around the hotel's pool and scores of injured Haitians lay outside the damaged hotel.

Bodies were visible all around the hilly city: under rubble, lying beside roads, being loaded into trucks. Scattered bodies were laid out on sidewalks, wrapped neatly in sheets and blankets. Voices cried out from the rubble.

Haitians wandered the chaotic, broken streets of Port-au-Prince, hoping desperately for assistance. Others clawed at chunks of concrete with bare hands and battered at slabs of debris with sledgehammers, trying to free those buried alive.

One young man yelled at reporters in English: "Too many people are dying. We need international help ... no emergency, no food, no phone, no water, no nothing."    

Asked by a CNN reporter how many people had died, Haitian President Rene Preval replied, "I don't know ... I heard 50,000 ... 30,000." He did not say where the estimates came from.

Canadian aid worker Danielle Trepanier was rescued on Wednesday, disoriented and in shock but otherwise with only minor scratches, after nearly 24 hours trapped in the debris of the collapsed house where she lived, aid group Doctors Without Borders said.

"Two locally recruited drivers were among those who put their own lives in danger to rescue Danielle, knowing from her intermittent cries for help that all was not lost," the group said in a statement.

Nations around the world pitched in to help. French Foreign Minister Bernard Kouchner said on Thursday French planes would evacuate 60 injured people from its one-time colony and fly them to Martinique for treatment. Others will be flown out later, he told France Inter Radio.

President Preval called the damage "unimaginable" and described stepping over dead bodies and hearing the cries of those trapped in the collapsed Parliament building.

"It's the worst I've ever seen," the Salvation Army's director of disaster services in Haiti, Bob Poff, told CNN. "It's so much devastation in a concentrated area. It's going to take days, or weeks, to dig out."    

The quake's epicenter was only 10 miles (16 km) from Port-au-Prince. About 4 million people live in and around the city, which was rocked by aftershocks as powerful as 5.9 magnitude.

Normal communications were cut off, roads were blocked by rubble and trees, electric power was interrupted and water was in short supply. The only lights visible in the city came from solar-powered traffic signals.

Haitian Red Cross spokesman Pericles Jean-Baptiste said his organization -- accustomed to dealing with disaster in a country dogged by poverty, catastrophic natural disasters and political instability -- was overwhelmed and out of medicine.

"There are too many people who need help. ... We lack equipment, we lack body bags," he told Reuters. UN peacekeeping personnel around the city seemed overwhelmed by the enormity of the recovery task ahead.

"We just don't know what to do," a Chilean peacekeeper said. "You can see how terrible the damage is. We have not been able to get into all the areas."    

US President Barack Obama spoke by phone to the UN secretary-general and the leaders of Brazil, Canada, Mexico and Chile about efforts to assist Haiti but was not able to contact Preval, the White House said.

Obama pledged swift, coordinated support and the Pentagon was sending an aircraft carrier and three amphibious ships, including one that can carry up to 2,000 Marines.

The United States, China and European states were sending reconnaissance and rescue teams, some with search dogs and heavy equipment, while other governments and aid groups offered tents, water purification units, food and telecoms teams.

The quake knocked out the Port-au-Prince airport control tower. The US Air Force sent a team to restore air traffic control to allow flights to evacuate the injured and bring in supplies.

Former US President Bill Clinton, UN special envoy to Haiti, said more rescue teams and heavy equipment were needed. "We need more helicopters," Clinton told CNN. "The most important thing is to get people into the (collapsed) buildings and find as many alive as possible." -Reuters