New York City officials say they have gathered new debris from in and around the World Trade Center site and will soon begin another round of sifting to uncover human remains.

Deputy Mayor Edward Skyler said Friday in a memo that 844 cubic yards of debris have been recovered since earlier sifting was completed in 2007. Anthropologists and others are expected to return to sifting in April and complete the work after about three months.

The new debris was uncovered as excavations and other work made new parts of the site and the area around it accessible.

The sifting will be done at the now-closed Fresh Kills landfill. So far, 1,772 potential human remains have been pulled from nearly 15,000 cubic yards of debris.