MIAMI -- A powerful 7.0-magnitude earthquake struck near the capital of Haiti Tuesday afternoon, crippling the poor island nation and knocking out most of its communication with the outside world.
There were no fatalities reported as of 8 p.m. EST, but there were growing reports of mass destruction -- a hospital is believed to have collapsed and people heard screaming for help.
Sections of the National Palace have crumbled and there were reports of injuries.
"There are people injured in the palace," said Fritz Longchanp, executive director of the palace. "I'm calling for help and medical assistance for them."
Haitian President Rene Preval and the first lady have sought safe haven on the island, The Miami Herald has learned.
Part of the road to Canape Vert has collapsed, as have houses in the mountains of Petionville, where the quake was centered. Petionville is a suburb some 10 miles from Port-au-Prince, the capital.
Several aftershocks have followed the main 4:53 p.m. earthquake, according to The Associated Press.
A blanket of dust completely covered the city for about 10 minutes, USAID contract employee Mike Godfrey told CNN from Port-au-Prince.
"At this point I'm frustrated trying to find colleagues and staff," Godfrey said. "Phones are not working. ... I see some traffic, a little traffic on some of the routes," he said.
Raymond Alcide Joseph, the country's ambassador to the U.S., told CNN that the quake has crippled his country.
"I spoke to a government official on the island who I reached on his cell phone and he told me: "Tell the world this is a catastrophe of major proportions."
President Barack Obama is monitoring the situation in Haiti, according to White House officials, and the State Department is working to confirm the safety of its personnel at the U.S. embassy in Port-au-Prince.
"My thoughts and prayers go out to those who have been affected by this earthquake," Obama said in a statement. "We are closely monitoring the situation and we stand ready to assist the people of Haiti."
Former President Bill Clinton, U.N. special envoy for Haiti, issued a statement offering assistance. "My thoughts and prayers are with the people of Haiti. My UN office and the rest of the UN system are monitoring the situation, and we are committed to do whatever we can to assist the people of Haiti in their relief, rebuilding and recovery efforts," he said.
In Hawaii, Secretary of State Hillary Clinton said America's thoughts were "with the people of Haiti."
In Miami, U.S. Rep. Ileana Ros-Lehtinen of Florida, the ranking Republican on the House Foreign Affairs Committee, said: "Of one thing you can be sure: Haiti is not alone. The U.S. will move hand in hand with the people of Haiti to swiftly respond to and recover from this tragedy. I call on all responsible nations to work together to implement a response which is immediate, targeted, coordinated and resilient."
The American Red Cross was poised to move aid from a warehouse in Panama -- blankets, kitchen sets and water containers for about 5,000 families -- as soon as a flight or means of delivery could be found, said Eric Porterfield in Washington, D.C.
Field reports, he said, indicated "lots of damage and lots of aftershocks."
In addition, the American Red Cross had already released $200,000 for its counterpart Haitian Red Cross.
The quake rattled the U.S. Navy base at Guantanamo Bay, Cuba, just after 5 p.m. where there was no immediate report of damage or injury.
"It felt like when a building shakes when a subway goes by. But I know there's no subway here and the island's not moving," said Army Maj. Diana R. Haynie.
At Southern Command in Miami, the military was on standby for a formal request from the Haitian government for assistance. None had been made.
South Florida Haitians dialed friends and relatives in the island nation -- to no avail. All connections were cut.
"My mother just went to Haiti on Friday and I'm terrified and I'm pretending I'm not," said Gepsie Metellus, a Haitian community leader.
(McClatchy Newspapers correspondents Frances Robles and Trenton Daniel of The Miami Herald contributed to this report.)