Superstorm Sandy inflicted "extensive" damage on the National September 11 Memorial, built at the World Trade Center site in New York to honor those killed in the 2001 attacks, an official said on Wednesday.
The memorial's chief executive Joe Daniels said the site had suffered "extensive impacts" due to "serious flooding" at the foundation level of the World Trade Center, where a museum is currently under construction.
Flooding also hit the visitor center and other facilities.
Daniels vowed to perform the necessary repairs and reopen the memorial "as soon as possible."
Ground Zero is in southern Manhattan, the New York City sector worst hit by floodwaters. Electricity is still out in the area.
At the memorial site, two reflecting pools sit in the footprints of the Twin Towers bronze panels along the edges of the pools bear the names of victims of the 9/11 attacks and the 1993 World Trade Center bombing.
The site was inaugurated during the 10th anniversary of the 9/11 attacks, which killed nearly 3,000 people in New York, at the Pentagon and in Shanksville, Pennsylvania.