International efforts to help Haiti in the wake of Tuesday's earthquake are picking up speed, as governments around the world and aid agencies mobilise search and rescue teams and aid supplies.
While the full scale of the disaster has yet to emerge, it is clear it represents a huge challenge.
Haiti, the poorest country in the western hemisphere, is still struggling to recover from devastating hurricanes in 2008.
So far, only a trickle of aid flights have arrived in Haiti, which needs all kinds of help - from search and rescue teams and medical aid, to food aid and then longer-term rebuilding of infrastructure.
The US is mobilising a huge military and civilian aid effort as President Barack Obama pledged a "swift, co-ordinated and aggressive" to save lives. He put the US international development agency -
in charge of co-ordinating the country's aid effort.
Military overflights have been assessing damage and civilian disaster assistance teams have begun arriving. The US military had ordered an aircraft carrier and three ships, including one which can carry up to 2,000 US Marines, to head for Haiti, officials said.
The Americans are playing a key role in central co-ordination on the ground in Haiti - largely because they have more functioning infrastructure than anyone else. The US embassy in the capital Port-au-Prince is intact; communications equipment for rescue teams has been flown in.
Haitian communities in the US itself - including south Florida where an estimated 275,000 Haitians live - are also organising donations and relief efforts.
Several international aid agencies have offices and staff in Haiti, usually working on long-term aid and reconstruction.
It is already evident that this is an extremely serious situation, the long-term effects of which are going to need substantial support
They began mobilising emergency teams in response to the quake.
says it has staff ready, including a public health, water and sanitation team in the capital, Port-au-Prince.
The organisation also had emergency supplies in Panama which could be taken in, a spokesman said.
The International Red Cross
says it is releasing emergency funds to help deal with the disaster. Red Cross warehouses in Port-au-Prince which survived the earthquake had basic aid for about 10,000 families and a further 20,000 aid kits are being transported from Panama, a spokesman said.
British Red Cross
has launched an appeal in the UK and has released £200,000 ($325,000) from its disaster fund to ensure money is immediately available.
The international humanitarian group,
Medecins Sans Frontieres (MSF),
said many people in Port-au-Prince had sought medical help, and that it had set up makeshift clinics offering basic care as its buildings had been seriously damaged.
MSF plans to send dozens more staff to Haiti to help workers based there.
UN Secretary-General Ban Ki-moon said $10m would be released immediately from the world body's central emergency response fund to assist aid efforts. He said an emergency appeal for additional funds from member states would follow.
Bill Clinton: ''What we need now is food, water, supplies''
UN World Food Programme
- which already runs extensive feeding operations in the country - said it would begin distributing high energy biscuits, which require no preparation before being consumed.
The WFP also said it would airlift 86 metric tons of food from its emergency hub in El Salvador, enough for 30,000 people in urgent need to be fed for up to seven days.
"In a normal day the World Food Programme will be feeding one or two million people in Haiti - and now we need to do even more, because the people have lost everything," a spokeswoman said.
The Minustah mission has more than 9,000 police and troops stationed in Haiti, as well as 488 international civilian staff and local staff. Its forces are drawn from more than 40 countries, including Brazil, China and Pakistan.
Several Minustah nations have said they are preparing to send aid.
The UN has set up a logistics centre at Haiti's main airport.
OTHER INTERNATIONAL RESPONSES
France, which has historic links with Haiti and some 1,400 nationals living there, is sending two planes with rescuers and humanitarian aid, one from the Caribbean island of Martinique and a second one with aid experts from Marseille. It also plans to evacuate about 60 injured people.
French civil safety authorities said a total of 130 rescuers, doctors and nurses as well as trained rescue dogs were due to arrive in Haiti, with 12 tonnes of aid and rescue material.
Peter Stevenson is Operations Commander for the UK's International Search and Rescue Team
Spain has pledged $4.3m (3m euros) and says it has 150 tonnes of humanitarian aid ready for delivery. The country has offered the EU the use of its humanitarian base in Panama to ferry in help.
Germany has released $2.18n (1.5m euros) in aid and has sent an immediate response team.
The Netherlands has donated $2.9m (2m euros) and Belgium, Sweden and Luxembourg are offering water purification equipment, tents, medical help and search-and-rescue experts.
Italy has prepared a military transport plane which will be used to take in a field hospital and emergency medical team.
The European Union says it has activated all "crisis and aid management mechanisms" and the
has released $4.3m (3m euros) in emergency assistance, the maximum for an emergency procedure.
The President of the EU, Herman van Rompuy, said "the EU stands ready to offer its assistance in any possible way".
Israel is sending an army rescue unit, including engineers, doctors and other medical staff.
China is to donate $1m, according to Xinhua News Agency.
Venezuela said it was sending a military plane with food, medicine and drinking water, as well as a team of 50 rescue workers.
Cuba, which also felt the quake, has sent 30 doctors.
Cuban field hospitals in Port-au-Prince were already treating hundreds of injured, according to Cuban Foreign Minister Bruno Rodriguez.
Canada has said it is sending a 20-person reconnaissance team to assess aid needs.
Mexico, which has long experience of dealing with devastating earthquakes, is sending a team of doctors and search and rescue workers and infrastructure damage experts.
The Inter-American Development Bank (IADB) is providing $200,000 (£122,000) in immediate emergency aid which can be used to provide food, potable water, medicines and temporary shelter.
The World Bank, whose local offices were destroyed in the earthquake, is planning to send a team to assess damage.
It has announced an extra $100m in emergency aid for Haiti, to help with recovery and reconstruction.
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