Police thwarted the demonstration Wednesday by locking the large steel gate about 30 minutes before the protesters arrived.
The protesters wore yellow clothing and held signs with messages like ``3,000 people consecrated this ground with their blood.'' They accused Gov. George Pataki of going back on a promise to never build on the footprints.
``An irreplaceable part of our American heritage is being systematically destroyed,'' said protester Beverly Eckert, who lost her husband in the 2001 attacks.
``My heart goes out to the families,'' Pataki said when asked about the protest. ``We're doing everything we can to be as respectful and supportive and understanding of the families' desires as possible.''
Reconstruction plans call for a memorial to preserve the approximate area the towers stood on. But infrastructure and other development would encroach on the footprints at bedrock level, an area viewed by some families as a sacred cemetery for the nearly 2,800 people who died there.
Eckert expressed fears that victims' children would visit the site, ``only to find their sacrifice is marked by a shopping mall and a subway stop.''
A rally for the same cause is planned for Sept. 10.