Yukio Takasu told the General Assembly at the end of its first session following the killer storm that the most serious damage was from flooding, which affected many basement offices and the cooling system in the main Secretariat building and caused a small fire.
UN safety and security chief Gregory Starr told the 193-member world body that the flooding also affected many electrical components and tore the sheeting off the top of the Secretariat building.
The sprawling UN complex is undergoing its first major renovation since it opened 60 years ago at a cost of about USD 2 billion.
Some of the 3,000 staffers forced to move to temporary offices around Manhattan recently started returning to the 39-storey Secretariat building.
Another 2,000 have remained on the 6.8-hectare site, including Secretary-General Ban Ki-moon and other senior officials, who work in a temporary building constructed just north of the main one, which was not affected by Sandy.
During a tour of the UN's third and bottom basement, a news agency’s correspondent saw staff members mopping floors and some areas nearest the East River still flooded.
Among the hard-hit areas were the UN receiving office, mail and supply rooms, where staffers said perhaps hundreds of thousands of dollars' worth of equipment, paper and supplies were damaged.
"This extreme weather event caused unprecedented damage on UN premises from Monday to Tuesday," Takasu told the General Assembly.
He said that because of damage to the cooling system the UN Security Council moved a meeting on Wednesday afternoon to the temporary building on the north lawn.
New York: The headquarters of the United Nations overlooking New York's East River suffered "unprecedented damage" from Superstorm Sandy, the UN management chief said on Thursday.
First Published: Friday, November 02, 2012, 10:25