Haiti's ambassador to the US issued an appeal for help in Washington on Tuesday after his homeland was rocked by a magnitude-7.0 earthquake.
Raymond Joseph said in an interview with CNN that an official he contacted in Port-au-Prince described "a catastrophe of major proportions" in the impoverished Caribbean nation.
"The only thing I can do now is pray and hope for the best," the envoy told CNN.
Shortly after Joseph's comments, President Barack Obama said the US was prepared to provide disaster assistance to Haiti, the poorest nation in the Western Hemisphere.
"We are closely monitoring the situation and we stand ready to assist the people of Haiti," the president said in a statement.
The temblor struck at 4.53 pm and its epicentre was about 15 km southwest of the Haitian capital. The initial event was followed by three aftershocks, including a magnitude-5.9 earthquake.
A tsunami warning issued for the coasts of Haiti, the neighbouring Dominican Republic and nearby Cuba and the Bahamas was lifted about two hours after the quake.
The earthquake knocked out both fixed-line and mobile telephone service in Port-au-Prince, a US State Department spokesman told EFE, while a Dominican government press officer said reports had reached Santo Domingo of "great damage" in the neighbouring country.
"The information we have point to a difficult situation in Haiti, so we ask that Latin America and the whole world come to the aid of our neighbour, as we are also ready to do," Rafael Nuñez told Dominican television.
Venezuela's foreign minister, Nicolas Maduro, announced that President Hugo Chavez had ordered the immediate dispatch to Haiti of relief supplies and search and recovery teams.