UNITED NATIONS - A large number of UN staffers are unaccounted for after a massive earthquake caused serious damage to their headquarters in Haiti, a senior UN official said here late Tuesday.

"For the moment, a large number of personnel remain unaccounted for," Alain Leroy, the head of the UN department of peacekeeping operations which oversees the world body's various missions around the world, said in a statement.

He said the headquarters of the United Nations Stabilization Mission in Haiti (MINUSTAH) in the Haitian capital "has sustained serious damage along with other UN installations."

"Contacts with the UN on the ground have been severely hampered as communications networks in Haiti have been disabled by the earthquake," he added.

MINUSTAH, which comprises 7,060 troops and 2,091 police, has been deployed in the impoverished Caribbean island-nation of eight million people since mid-2004.

Meanwhile UN chief Ban Ki-moon issued a statement saying "my heart goes out to the people of Haiti after this devastating earthquake.

"At this time of tragedy, I am very concerned for the people of Haiti and also for the many United Nations staff who serve there."