The international effort to help survivors of the massive earthquake in Haiti has intensified, with up to 3m people thought to be injured or homeless.
A senior Haitian Red Cross official told reporters that the death toll could reach 50,000, while Haitian Prime Minister Jean-Max Bellerive earlier expressed fears that it could be far higher.
US and Chinese rescue teams are among those to have arrived in the capital Port-au-Prince, bringing specialist equipment, food and medical aid.
It is estimated that up to 3m people will need humanitarian aid following the quake.
Rescuers, sniffer dogs, supplies and promises of funds make up the initial global response to the disaster.
Much of Port-au-Prince was reduced to rubble by Tuesday's 7.0-magnitude quake, however the airport is operational.
UN Secretary General Ban Ki-moon has said that at least 36 UN workers were killed and 150 are still missing.
Mr Ban said the dead were troops and police serving with the UN mission the capital.
US troops and ships have been dispatched to assist in earthquake rescue and recovery efforts. US President Barack Obama added that the US will spend $100m on immediate relief efforts.
'The priority is to find survivors,' Elisabeth Byrs, a spokeswoman for the UN's Office for the Coordination of Humanitarian Affairs, said as the UN mobilised search and rescue teams.
'We are working against the clock,' she said.
General Douglas Fraser, head of the US Southern Command, told reporters that an initial aerial survey indicated the damage was mainly concentrated around the capital. However, the number of casualties and the scale of the disaster is still unknown.
'We don't have a clear assessment right now of what the situation on the ground is,' he said.
Former US president Bill Clinton, now the UN special envoy in Haiti, has launched a quake fund, saying 'even a dollar or two' would help, while Pope Benedict XVI has urged a generous response to the 'tragic situation'.
The World Bank is to provide an extra $100m in funds to Haiti, which has long suffered unrest, crime, political tumult and natural disasters.
'This is a shocking event and it is crucial that the international community supports the Haitian people at this critical time,' said Robert Zoellick, president of the 186-nation development lender.
The head of the International Monetary Fund, Dominique Strauss-Kahn, has said it will also provide $100m in aid.
The International Federation of Red Cross and Red Crescent Societies is gearing up to help a 'maximum of 3m people', based on numbers on the ground, and is drawing on emergency stocks in Haiti.
The Red Cross has launched a $10m appeal for donations and the World Food Programme said it could quickly provide 15,000 tonnes of food.
The World Health Organisation has also deployed specialists to help handle mass casualties and corpses, warning of the danger of disease.
Neighbouring Cuba, which also felt the quake and evacuated some 30,000 people following a brief tsunami alert, has sent 30 doctors.
Some 400 Cuban medical staff already in Haiti were largely unharmed and there are currently two Cuban field hospitals in Port-au-Prince.
Latin American nations, many with experience of earthquakes and with UN peacekeepers in Haiti, have also offered help.
Brazil is sending $10m in immediate aid, while Peru, Venezuela, Mexico, Colombia, Guatemala and Chile have also promised help.
Canada has filled military vessels, helicopters and planes with supplies and is providing a large relief and rescue force.
From the Asia-Pacific, Australia pledged $9m. Taiwan, whose ambassador to Haiti was hurt in the quake, South Korea and New Zealand also offered aid.
In Europe, the European Commission has released €3m in emergency assistance, while Britain, France, Germany, Italy, the Netherlands and Spain all volunteered help.
A plane carrying search and rescue teams left from Moscow and Russia has pledged to send a field hospital.
Ireland has already put €20m into the UN's Emergency Fund, but Minister for Foreign Affairs Micheál Martin has pledged additional money.
The Government is to send a team of experts to Haiti to assist in the international emergency effort.
The technical team will be drawn from Irish Aid, which is the Government's programme for overseas development.
The Taoiseach has expressed sympathy for the Haitian people. Brian Cowen said Ireland would work with the international community to alleviate the hardship.
Appeals for aid
Concern Worldwide, which has been working in Haiti since 1994, has launched an emergency appeal following the earthquake.
Donations will be accepted on 1850-410510 or through Concern.net.
People can donate to Oxfam by calling 1850-304055 (NI 0800-0304055), by visiting OxfamIreland.org, or at their local Oxfam Ireland shop.
GOAL has allocated €250,000 from its emergency fund as an immediate response and is accepting donations from the public. Call 01-2809779 or visit Goal.ie.
UNICEF Ireland has launched an emergency appeal for the children of Haiti. Donations can be made on Unicef.ie or by calling 01-8783000.
Médecins Sans Frontières can be contacted on 1800 905 509 and is also accepting donations on MSF.ie
Trócaire has also appealed for funds. To donate, visit Trocaire.org or call 1850-408408 (NI: 0800-9121200).
The Irish Red Cross launched an emergency appeal also, donations are being accepted online at Redcross.ie or by calling 1850-507070.
Haven is appealing for funds for its emergency earthquake relief. You can donate securely via www.havenpartnership.com or cheques can be sent to Haven, the Malthouse, Grand Canal Quay, Dublin 2.
World Vision Ireland has launched a Haiti Earthquake appeal and is accepting donations online at www.worldvision.ie or by calling 1850-366283.
Christian Aid has launched an appeal and released €100,000 to help local partner organisations in Haiti. To donate please call [Dublin] 01-6110801 or [Belfast] 028-90381204 or at ChristianAid.ie.