Mayor Michael Bloomberg hosted a World Trade Center summit at Grace Mansion Thursday to try to resolve construction delays at the site.

Developer Larry Silverstein, Port Authority officials, Governor David Paterson and New Jersey Governor John Corzine talked to begin to get negotiations moving.

The initial plan was to build five towers at the 16-acre site, but Silverstein has been unable to get financing and wants the Port Authority to back at least two of buildings.

Port Authority officials said they would back one tower with $800 million if Silverstein invests more money into infrastructure, including the transit hub and September 11th memorial.

"We're not going to come out with a solution today, that's just not going to happen," said Bloomberg. "We've got a private developer and we've got the Port Authority, and we'll have everybody in one room the and real mission is to have everybody talking and understand the urgency and understand how important it is to this city and to this country that we continue to develop the World Trade Center site."

The $3.2 billion hub is five years behind schedule.