Haiti's devastating earthquake has left an estimated 3 million people in need of emergency aid, a Red Cross official said Wednesday, as aid groups and governments scrambled to send tons of disaster relief to the impoverished Caribbean nation.
Humanitarian officials said the proximity of the quake's epicenter, only 10 miles (15 kilometers) from the capital Port-au-Prince, and Haiti's crumbling infrastructure meant it was impossible to gauge exactly how many people might be dead or wounded.
"There's probably 3 million people potentially affected," said Paul Conneally, spokesman for the International Federation of Red Cross and Red Crescent societies.
The first airlifts to Haiti concentrated on search and rescue efforts and setting up makeshift hospitals.
U.S. Secretary of State Hillary Rodham Clinton said the United States was offering full assistance -- civilian and military. Prime Minister Gordon Brown said Britain would provide "whatever humanitarian assistance is required," while France, Canada, China, Germany, Mexico and Venezuela pledged immediate support in terms of personnel, cash and supplies.
Germany said it would donate euro1 million ($1.45 million), while China pledged $1 million.
One of the first teams expected to arrive Wednesday was 37 search and rescue specialists from Iceland, who are bringing with them 10 tons of their own equipment.
French rescue authorities say 65 clearing specialists and 6 sniffer dogs are leaving for Haiti on Wednesday, while Spain is rushing three airplanes to Haiti with at least 100 tons of tents, blankets and cooking kits. Israel is sending in an elite Army rescue unit of engineers and medics.
The Red Cross said Haiti's disaster relief teams were "completely overwhelmed."
"There's no structured response at this point," spokesman Simon Schorno told The Associated Press.
The United Nations is also deploying a disaster coordination team to Haiti.
Officials were struggling to assess the scale of the disaster amid badly damaged communication networks, said Elizabeth Byrs, a U.N. humanitarian spokeswoman, but it was working with aid agency Telecoms Sans Frontieres to immediately get phone lines working.
There is no electricity in the capital, and roads are filled with obstacles and debris, she added. Port-au-Prince's airport remains open, but the artery connecting it to the city is blocked, so aid officials were still trying to decide on the best way to rush lifesaving assistance.
U.N. agencies and Red Cross societies were trying to send in teams and aid from their regional hub in Panama, while USAID is mobilizing a response group and two urban search and rescue units, Byrs said.
If aid cannot travel over the airport road, assistance may be rerouted through the Dominican Republic, said Charles Vincent, a senior World Food Program official, whose agency plans to airlift tons of high-energy biscuits from El Salvador, enough to feed 30,000 people for a week.
"The first priority is to save lives," Vincent told reporters.
Byrs said the neighboring Haitian cities of Carrefour and Jacmel may also be heavily damaged.
Conneally said his estimate of the Haitians affected relied on previous Red Cross experience in earthquake relief.
"Port-au-Prince has been massively impacted," Conneally said. "There are many, many people trapped in the rubble."
He said emergency shelter and long-term rebuilding efforts could easily require a year of aid work.
At the Vatican, Pope Benedict XVI appealed for a generous international aid response for the quake victims and pledged the Catholic Church's support.
The Christian aid organization World Vision, which has 400 staff in Haiti, said it would immediately distribute supplies it had stored in Haiti for hurricane relief.
Low-lying areas of Port-au-Prince, including the Cite Soleil slum, appeared to be hit worse than neighborhoods higher up the hills, said World Vision spokesman Casey Calamusa.
Maggie Boyer, the World Vision spokeswoman in Haiti, said the moment the quake hit felt "like a truck had run into her building," he added.
AP writers Jenny Barchfield in Paris, Nicole Winfield in Rome, Raphael G. Satter and Jane Wardell in London, Scott McDonald in Beijing, Kirsten Grieshaber in Berlin and Daniel Woolls in Madrid contributed to this report.