"My heart goes out to the people of Haiti after this devastating earthquake," he said in a statement issued on Tuesday night. "I am receiving initial reports and following developments closely."
The 7.0-magnitude quake reportedly hit south-west of the capital, Port-au-Prince, late this afternoon.
The Under-Secretary-General for Peacekeeping said that contacts with the UN on the ground have been severely hampered as communications networks in Haiti have been disabled by the quake.
"For the moment, a large number of personnel remain unaccounted for," Alain Le Roy said in a statement.
He added that the headquarters of the UN Stabilization Mission in Haiti (MINUSTAH) in Port-au-Prince has sustained serious damage along with other UN installations.
"The Department of Peacekeeping Operations is still in the process of gathering information on the extent of the damage and the status of UN personnel," stated Mr. Le Roy.
MINUSTAH was set up in 2004 and currently has more than 9,000 military and police personnel and nearly 2,000 civilian staff.