NYPD Commissioner Raymond Kelly says the World Trade Center site will eventually have 673 officers assigned to it.
Kelly spoke about the need for securing the site at an event Tuesday for the nonprofit Police Foundation.
The 9/11 memorial will open on Sept. 11, 2011, and after that the new buildings.
Kelly has named a deputy commissioner for the World Trade Center command who is working on a security plan for the memorial service.
Kelly says the site needs special attention because it was attacked twice, and remains a target for terrorists.