PORT-AU-PRINCE, Haiti (AP) – The strongest earthquake in more than 200 years rocked Haiti on Tuesday, collapsing a hospital where people screamed for help and heavily damaging the National Palace, UN peacekeeper headquarters and other buildings. Thousands are feared to have been killed.

United Nations officials said a large number of UN personnel were unaccounted for. The Philippines has a large contingent of peacekeepers in the impoverished Caribbean nation, and the Department of Foreign Affairs in Manila admitted they are having difficulty establishing communication with the Filipinos in Haiti.

US officials reported bodies in the streets and an aid official described "total disaster and chaos”.

Communications were widely disrupted, making it impossible to get a full picture of damage as powerful aftershocks shook a desperately poor country where many buildings are flimsy. Electricity was out in some places.

Karel Zelenka, a Catholic Relief Services representative in the capital Port-au-Prince, told US colleagues before phone service failed that "there must be thousands of people dead," according to a spokeswoman for the aid group, Sara Fajardo.

"He reported that it was just total disaster and chaos, that there were clouds of dust surrounding Port-au-Prince," Fajardo said from the group's offices in Maryland.

State Department spokesman P.J. Crowley said in Washington that embassy personnel were "literally in the dark" after power failed.

"They reported structures down. They reported a lot of walls down. They did see a number of bodies in the street and on the sidewalk that had been hit by debris. So clearly, there's going to be serious loss of life in this," he said.

Alain Le Roy, the UN peacekeeping chief in New York, said late Tuesday that the headquarters of the 9,000-member Haiti peacekeeping mission and other UN installations were seriously damaged.

"Contacts with the UN on the ground have been severely hampered," Le Roy said in a statement, adding: "For the moment, a large number of personnel remain unaccounted for.”

The DFA in Manila expressed concerns over the safety of Filipinos in the country.

“The DFA is deeply concerned over the condition of Filipinos in Haiti following the magnitude 7.0 earthquake that struck Port-au-Prince on January 12,” DFA spokesman J. Eduardo Malaya said.

“Communications to and from Haiti have been damaged during the quake. The DFA will provide the public with updates as soon as reports are received from New York or the Philippine Embassy in Havana, Cuba, which covers Haiti,” he said.

There are 157 officers of the Armed Forces of the Philippines and 22 from the Philippine National Police currently serving with the UN peacekeeping contingent in Haiti. There is also an estimated 440 members of the Filipino community in the country.

“The UN headquarters in NY has also not been able to communicate with the MINUSTAH (UN Stabilization Mission in Haiti) in Port-au-Prince,” Malaya said.

In a television interview, Philippine Mission to the UN First Secretary and press officer Elmer Cato said UN Permanent Representative Ambassador Hilario Davide is expected to send his recommendations to Manila if there is a need for additional Philippines troops that would help in the rescue operations in Haiti. A UN meeting is scheduled Wednesday morning, New York time.

“We will monitor the situation until we get in touch with the [Philippine] contingent,” Cato said.

Felix Augustin, Haiti's consul general in New York, said a portion of the National Palace had disintegrated.

"Buildings collapsed all over the place," he said. "We have lives that are destroyed. ... It will take at least two or three days for people to know what's going on."

An Associated Press videographer saw the wrecked hospital in Petionville, a hillside Port-au-Prince district that is home to many diplomats and wealthy Haitians, as well as many poor people. Elsewhere in the capital, a US government official reported seeing houses that had tumbled into a ravine.

Kenson Calixte of Boston spoke to an uncle and cousin in Port-au-Prince shortly after the earthquake by phone. He could hear screaming in the background as his relatives described the frantic scene in the streets. His uncle told him that a small hotel near their home had collapsed, with people inside.

"They told me it was total chaos, a lot of devastation," he said. More than four hours later, he still was not able to get them back on the phone for an update.

Haiti's ambassador to the US, Raymond Joseph, said from his Washington office that he spoke to President Rene Preval's chief of staff, Fritz Longchamp, just after the quake hit. He said Longchamp told him that "buildings were crumbling right and left" near the national palace. He too had not been able to get through by phone to Haiti since.

The earthquake had a preliminary magnitude of 7.0 and was centered about 10 miles (15 kilometers) west of Port-au-Prince at a depth of 5 miles (8 kilometers), the US Geological Survey said. USGS geophysicist Kristin Marano called it the strongest earthquake since 1770 in what is now Haiti.

The temblor appeared to have occurred along a strike-slip fault, where one side of a vertical fault slips horizontally past the other, said earthquake expert Tom Jordan at the University of Southern California. The earthquake's size and proximity to populated Port-au-Prince likely caused widespread casualties and structural damage, he said. (With a report from Madel R. Sabater)