"When the earthquake struck, I was driving down the mountain. Our truck was being tossed to and fro like a toy, and when it stopped, I looked out the windows to see buildings 'pancaking'.
People poured out into the streets, crying, carrying bloody bodies, looking for anyone who could help them. We piled as many bodies as we could into the back of our truck, and took them down the hill with us, hoping to find medical attention.
"All of them were scared, bleeding and terrified. The children, and hundreds of neighbours, are sleeping in our playground area tonight. Occasionally, there is another tremor and all of the people cry out and the children are terrified."
Bob Poff, Salvation Army in Haiti
"At Christmas we'd all breathed a collective sign of relief; we were so grateful to have got through the hurricane season without a major disaster. People were looking forward to the carnival, just a couple of weeks away. Then the quake struck.
"The city is a mess; it looks like a war zone. Then there's the issue of clean water: it's a problem in Haiti under the best of circumstances, it will have only been exacerbated. Another of the challenges is to keep hope. People are in shock.
"They are walking around, shaking their heads and saying 'What next?' In Haiti, we seem to make good progress and then something happens and reverses it."
Magalie Boyer, World Vision aid worker
"I was in the intensive care room looking after a nine-month-old baby girl when the earthquake hit. The floor started shaking violently and the whole building shook from side to side. It lasted about 45 seconds. After that, there was a constant shuddering.
"The babies were really frightened and started to cry. Other staff and carers were screaming, they were so terrified. It was very upsetting."
Susan Westwood, Paediatric nurse in Port-au-Prince
"This is an earthquake unlike anything Haiti has ever experienced. I cannot stress enough what a human disaster this is, and idle hands will only make this tragedy worse. We must act now. The US military is the only group trained and prepared to offer that assistance.
"They must do so as soon as possible. The international community must also rise to the occasion and help the Haitian people in every way possible."
Wyclef Jean, Haitian-born rap star
"The sun is about to come up. The aftershocks continue. There is no way to even begin to share the things we've heard and seen since 5pm on Tuesday. To do so would take hours that we don't have right now. Some of them feel wrong to tell; like only God should know these personal horrible tragedies.
"Thousands of people are trapped. Precious lives hang in the balance. When pulled from the rubble there is no place to take them for care; Haiti has an almost non-existent medical-care system. I cannot imagine what the next few weeks and months will be like. I am afraid for everyone."
Troy Livesay, Haiti resident
The Disasters Emergency Committee – the umbrella organisation for 13 aid agencies including the British Red Cross and Oxfam – has launched an emergency appeal to help the victims of the Haiti earthquake. If you would like to make a donation, please call 0370 60 60 900 or visit www.dec.org.uk